radiation damage选择____________prevent a lot of radiation damage[A] get[B] make[C] have[D] do

You will have a great conversation and maybe even get a date or make a new friend.

A: talk
B: speech
C: debate
D: discussion

Space is a dangerous place,not only because of meteors but also because of rays from the sun?and other stars.The atmosphere again acts as our protective blanket on earth.Light gets through,and?this is essential for plants to make the food which we eat.Heat,too,makes our environment endurable.Various kinds of rays come through the air from outer space,but enormous quantities of radiation from the sun are screened off.As soon as men leave the atmosphere they are exposed to this radiation.But their spacesuits or the walls of their spacecraft,if they are inside,do prevent a lot of radiation damage.
Radiation is the greatest known danger to explorers in space.The unit of radiation is called"rein".Scientists have reason to think that a man can put up with far more radiation than 0.1 rem?without being damaged;the figure of 60 rems has been agreed on.The trouble is that it is extremely?difficult to be sure about radiation damage—a person may feel perfectly well,but the cells of his or?her sex organs may be damaged,and this will not be discovered until the birth of deformed(畸形的)children or even grandchildren.Missions of the Apollo flights have had to cross belts of high radiation?and,during the outward and return journeys,the Apollo crew accumulated a large amount of rems.So?far,no dangerous amounts of radiation have been reported,but the Apollo missions have been quite?short.We simply do not know yet how men are going to get on when they spend weeks and months?outside the protection of the atmosphere,working in a space laboratory.Drugs might help to decrease?the damage done by radiation,but no really effective ones have been found so far.

We know from the passage that__

A.exposure to even tiny amounts of radiation is fatal
B.the effect of exposure to radiation is slow in coming
C.radiation is avoidable in space exploration
D.astronauts in spacesuits needn't worry about radiation damage

Space is a dangerous place,not only because of meteors but also because of rays from the sun?and other stars.The atmosphere again acts as our protective blanket on earth.Light gets through,and?this is essential for plants to make the food which we eat.Heat,too,makes our environment endurable.Various kinds of rays come through the air from outer space,but enormous quantities of radiation from the sun are screened off.As soon as men leave the atmosphere they are exposed to this radiation.But their spacesuits or the walls of their spacecraft,if they are inside,do prevent a lot of radiation damage.
Radiation is the greatest known danger to explorers in space.The unit of radiation is called"rein".Scientists have reason to think that a man can put up with far more radiation than 0.1 rem?without being damaged;the figure of 60 rems has been agreed on.The trouble is that it is extremely?difficult to be sure about radiation damage—a person may feel perfectly well,but the cells of his or?her sex organs may be damaged,and this will not be discovered until the birth of deformed(畸形的)children or even grandchildren.Missions of the Apollo flights have had to cross belts of high radiation?and,during the outward and return journeys,the Apollo crew accumulated a large amount of rems.So?far,no dangerous amounts of radiation have been reported,but the Apollo missions have been quite?short.We simply do not know yet how men are going to get on when they spend weeks and months?outside the protection of the atmosphere,working in a space laboratory.Drugs might help to decrease?the damage done by radiation,but no really effective ones have been found so far.

According to the first paragraph,the atmosphere is essential to man in that__________.

A.it protects him against the harmful rays from space
B.it provides sufficient light for plant growth
C.it supplies the heat necessary for human survival
D.it screens off the falling meteors

What is implied in “if you do get on eventually，just make sure to take both ways before crossing the street!”?

A You will be too excited to watch the traffic.
B Enjoying electronic devices while walking may invite traffic accidents.
C It is not possible for you to get such a backpack.
D It is wise of you to have such a backpack.

共用题干
第三篇

Nuclear Power and Its Danger

Nqclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.
Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.
It can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other things
like that.For example,radio waves are all around us but we can't detect them,sense them,without a radio
receiver.Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,
nuclear radiation is not harmless to human beings and other living things.
At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital or-
gans.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely
safe.if the radiation does not hit anything important,the damage may not be significant. This is the case when only
a few cells are hit,and if they are killed outright.Your body will replace the dead cells with healthy ones. But if the few
cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce them-
selves in a deformed way. They can grow into cancer. Sometimes this does not show up for many years.
This is another reason for some of the mystery about nuclear radiation.Serious damage can be done with-
out the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,
then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to
serious illness as result of radiation absorbed by its grandparents.
Radiation can hurt us.We must know the truth.

Radiation can cause serious consequences even at the lowest level_________.
A:when it kills few cells
B:if it damages few cells
C:though the damaged cells can repair themselves
D:unless the damaged cells can reproduce themselves

共用题干
第一篇

Nuclear Power and Its Danger

Nuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.
Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.It can't be seen or heard,or touched or tasted,even though it may be all around us.There are other things like that. For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,nuclear radiation is not harmless to human beings and other living things.
At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant. This is the case when only a few cells are hit,and if they are killed outright,your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.They can grow into cancer. Sometimes this does not show up for many years.
This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as result of radiation absorbed by its grandparents.
Radiation can hurt us.We must know the truth.

Radiation can hurt us in the way that it can________.
A:kill large numbers of cells in main organs so as to cause death immediately
B:damage cells which may grow into cancer years later
C:affect the healthy growth of our offspring
D:all of the above

共用题干
第一篇

Nuclear Power and Its Danger

Nuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.
Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.It can't be seen or heard,or touched or tasted,even though it may be all around us.There are other things like that. For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,nuclear radiation is not harmless to human beings and other living things.
At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant. This is the case when only a few cells are hit,and if they are killed outright,your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.They can grow into cancer. Sometimes this does not show up for many years.
This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as result of radiation absorbed by its grandparents.
Radiation can hurt us.We must know the truth.

The word"significant"in Paragraph 3 most probably means________.
A:fatal
B:meaningful
C:remarkable
D:harmful

共用题干
Nuclear Power and Its Danger
Nuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.
Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.
lt can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other things like that.For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver.Similarly,we can't sense radioactivity without a radiation detector.But unlike common radio waves, nuclear radiation is not harmless to human beings and other living things.
At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant．This is the case when only a few cells are hit,and if they are killed outnght.Your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.They can grow into cancer.Sometimes this does not show up for many years.
This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as a result of radiation absorbed by its grandparents.
Radiation can hurt us.We must know the truth.

Radiation1 can cause serious consequences even at the lowest level______.
A:when it kills few cells
B:if it damages few cells
C:though the damaged cells can repair themselves
D:unless the damaged cells can reproduce themselves

共用题干
第三篇

Nuclear Power and Its Danger

Nuclear power's danger to health,safety,and even life itself can be summed up in one word:radia-
tion.
Nuclear radiation has a certain mystery about it,partly because it canhot be detected by human senses.
It can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other
things like that.For example,radio waves are all around us but we can't detect them,sense them,without a
radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio
waves,nuclear radiation is not harmless to human beings and other living things.
At very high levels,radiation can kill an animal or human being outright by killing masses of cells in
vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that
is completely safe.If the radiation does not hit anything important,the damage may not be significant. This
is the case when only a few cells are hit,and if they are killed outright.Your body will replace the dead
cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be
in trouble.They reproduce themselves in a deformed way. They can grow into cancer. Sometimes this does
not show up for many years.
This is another reason for some of the mystery about nuclear radiation.Serious damage can be done
without the victim being aware at the time that damage has occurred.A person can be irradiated and feel
fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to
serious illness as result of radiation absorbed by its grandparents.
Radiation can hurt us.We must know the truth.

Radiation can hurt us in the way that it can__________.
A:kill large numbers of cells in main organs so as to cause death immediately
B:damage cells which may grow into cancer years later
C:affect the healthy growth of our offspring
D:all of the above

共用题干
Nuclear Power and Its Danger
Nuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation. Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.
It can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other things like that.For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver.Similarly,we can't sense radioactivity without a radiation detector.But unlike common radio waves,nuclear radiation is not harmless to human beings and other living things.
At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant.This is the case when only a few cells are hit,and if they are killed outright.Your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.They can grow into cancer.Sometimes this does not show up for many years.
This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as a result of radiation absorbed by its grandparents.
Radiation can hurt us.We must know the truth.

The underlined word"significant"in Paragraph 3 most probably means______.
A:fatal
B:meaningful
C:remarkable
D:harmful

You will have a great conversation and maybe even get a date or make a new friend.

A:talk
B:speech
C:debate
D:discussion

Space is a dangerous place,not only because of meteors but also because of rays from the sun?and other stars.The atmosphere again acts as our protective blanket on earth.Light gets through,and?this is essential for plants to make the food which we eat.Heat,too,makes our environment endurable.Various kinds of rays come through the air from outer space,but enormous quantities of radiation from the sun are screened off.As soon as men leave the atmosphere they are exposed to this radiation.But their spacesuits or the walls of their spacecraft,if they are inside,do prevent a lot of radiation damage.
Radiation is the greatest known danger to explorers in space.The unit of radiation is called"rein".Scientists have reason to think that a man can put up with far more radiation than 0.1 rem?without being damaged;the figure of 60 rems has been agreed on.The trouble is that it is extremely?difficult to be sure about radiation damage—a person may feel perfectly well,but the cells of his or?her sex organs may be damaged,and this will not be discovered until the birth of deformed(畸形的)children or even grandchildren.Missions of the Apollo flights have had to cross belts of high radiation?and,during the outward and return journeys,the Apollo crew accumulated a large amount of rems.So?far,no dangerous amounts of radiation have been reported,but the Apollo missions have been quite?short.We simply do not know yet how men are going to get on when they spend weeks and months?outside the protection of the atmosphere,working in a space laboratory.Drugs might help to decrease?the damage done by radiation,but no really effective ones have been found so far.

It can be inferred from the passage that__

A.the Apollo mission was very successful
B.protection from space radiation is no easy job
C.astronauts will have deformed children or grandchildren
D.radiation is not a threat to well-protected space explorers

Space is a dangerous place,not only because of meteors but also because of rays from the sun?and other stars.The atmosphere again acts as our protective blanket on earth.Light gets through,and?this is essential for plants to make the food which we eat.Heat,too,makes our environment endurable.Various kinds of rays come through the air from outer space,but enormous quantities of radiation from the sun are screened off.As soon as men leave the atmosphere they are exposed to this radiation.But their spacesuits or the walls of their spacecraft,if they are inside,do prevent a lot of radiation damage.
Radiation is the greatest known danger to explorers in space.The unit of radiation is called"rein".Scientists have reason to think that a man can put up with far more radiation than 0.1 rem?without being damaged;the figure of 60 rems has been agreed on.The trouble is that it is extremely?difficult to be sure about radiation damage—a person may feel perfectly well,but the cells of his or?her sex organs may be damaged,and this will not be discovered until the birth of deformed(畸形的)children or even grandchildren.Missions of the Apollo flights have had to cross belts of high radiation?and,during the outward and return journeys,the Apollo crew accumulated a large amount of rems.So?far,no dangerous amounts of radiation have been reported,but the Apollo missions have been quite?short.We simply do not know yet how men are going to get on when they spend weeks and months?outside the protection of the atmosphere,working in a space laboratory.Drugs might help to decrease?the damage done by radiation,but no really effective ones have been found so far.

The best title for this passage would be__

A.The Atmosphere and Our Environment
B.Research on Radiation
C.Effects of Space Radiation
D.Importance of Protection Against Radiation

共用题干
Nuclear Power and Its Danger
Nuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.
Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.
lt can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other things like that.For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver.Similarly,we can't sense radioactivity without a radiation detector.But unlike common radio waves, nuclear radiation is not harmless to human beings and other living things.
At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant．This is the case when only a few cells are hit,and if they are killed outnght.Your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.They can grow into cancer.Sometimes this does not show up for many years.
This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as a result of radiation absorbed by its grandparents.
Radiation can hurt us.We must know the truth.

The underlined word"significant"in Paragraph 3 most probably means______.
A:fatal
B:meaningful
C:remarkable
D:harmful

共用题干
第三篇

Nuclear Power and Its Danger

Nqclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.
Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.
It can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other things
like that.For example,radio waves are all around us but we can't detect them,sense them,without a radio
receiver.Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,
nuclear radiation is not harmless to human beings and other living things.
At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital or-
gans.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely
safe.if the radiation does not hit anything important,the damage may not be significant. This is the case when only
a few cells are hit,and if they are killed outright.Your body will replace the dead cells with healthy ones. But if the few
cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce them-
selves in a deformed way. They can grow into cancer. Sometimes this does not show up for many years.
This is another reason for some of the mystery about nuclear radiation.Serious damage can be done with-
out the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,
then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to
serious illness as result of radiation absorbed by its grandparents.
Radiation can hurt us.We must know the truth.

Which of the following can be best inferred from the passage?
A:The importance of protection from radiation cannot be over-emphasized.
B:The mystery about radiation remains unsolved.
C:Cancer is mnainly caused by radiation.
D:Radiation can hurt those who are not aware of its danger.

共用题干
第一篇

Nuclear Power and Its Danger

Nuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.
Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.It can't be seen or heard,or touched or tasted,even though it may be all around us.There are other things like that. For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,nuclear radiation is not harmless to human beings and other living things.
At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant. This is the case when only a few cells are hit,and if they are killed outright,your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.They can grow into cancer. Sometimes this does not show up for many years.
This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as result of radiation absorbed by its grandparents.
Radiation can hurt us.We must know the truth.

According to the passage,the danger of nuclear power lies in________.
A:nuclear mystery
B:radiation detection
C:nuclear radiation
D:radiation level

共用题干
Nuclear Power and Its Danger
Nuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.
Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.
lt can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other things like that.For example,radio waves are all around us but we can't detect them,sense them,without a radio receiver.Similarly,we can't sense radioactivity without a radiation detector.But unlike common radio waves, nuclear radiation is not harmless to human beings and other living things.
At very high levels,radiation can kill an animal or human being outright by killing masses of cells in vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is completely safe.If the radiation does not hit anything important,the damage may not be significant．This is the case when only a few cells are hit,and if they are killed outnght.Your body will replace the dead cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in trouble.They reproduce themselves in a deformed way.They can grow into cancer.Sometimes this does not show up for many years.
This is another reason for some of the mystery about nuclear radiation.Serious damage can be done without the victim being aware at the time that damage has occurred.A person can be irradiated and feel fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as a result of radiation absorbed by its grandparents.
Radiation can hurt us.We must know the truth.

According to the passage,the danger of nuclear power lies in______.
A:nuclear mysiery
B:radiation detection
C:nuclear radiation
D:radiation level

共用题干
第二篇

Nuclear Power and Its Danger

Nuclear power's danger to health,safety,and even life itself can be summed up in one word:radiation.
Nuclear radiation has a certain mystery about it,partly because it cannot be detected by human senses.
It can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other things
like that.For example,radio waves are all around us but we can't detect them,sense them,without a radio
receiver.Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio waves,
nuclear radiation is not harmless to'human beings and other living things.
At very high levels,radiation can kill an animal or human being outright by killing masses of cells in
vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that is
comnpletely safe.If the radiation does not hit anything important,the damage may not be significant.This is
the case when only a few cells are hit,and if they are killed outright.Your body will replace the dead cells
with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be in
trouble.They reproduce themselves in a deformed way.They can grow into cancer. Sometimes this does not
show up for many years.
There is another reason for the mystery of nuclear radiation.Serious damage can be done without the
victim being aware at the time that damage occurs. A person can be irradiated and feel fine,then die of cancer
five,ten,or twenty years later as a result.Or a child can be born weak or liable to serious illness as a result
of radiation absorbed by its grandparents.
Radiation can hurt us.We must know the truth.

The underlined word"significant"in Paragraph 3 most probably means_______________.
A: fatal
B:meaningful
C:remarkable
D:harmful

共用题干
第三篇

Nuclear Power and Its Danger

Nuclear power's danger to health,safety,and even life itself can be summed up in one word:radia-
tion.
Nuclear radiation has a certain mystery about it,partly because it canhot be detected by human senses.
It can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other
things like that.For example,radio waves are all around us but we can't detect them,sense them,without a
radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio
waves,nuclear radiation is not harmless to human beings and other living things.
At very high levels,radiation can kill an animal or human being outright by killing masses of cells in
vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that
is completely safe.If the radiation does not hit anything important,the damage may not be significant. This
is the case when only a few cells are hit,and if they are killed outright.Your body will replace the dead
cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be
in trouble.They reproduce themselves in a deformed way. They can grow into cancer. Sometimes this does
not show up for many years.
This is another reason for some of the mystery about nuclear radiation.Serious damage can be done
without the victim being aware at the time that damage has occurred.A person can be irradiated and feel
fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to
serious illness as result of radiation absorbed by its grandparents.
Radiation can hurt us.We must know the truth.

Which of the following can be best inferred from the passage?
A:The importance of protection from radiation cannot be over-emphasized.
B:The mystery about radiation remains unsolved.
C:Cancer is mainly caused by radiation.
D:Radiation can hurt those who are not aware of its danger.

共用题干
第三篇

Nuclear Power and Its Danger

Nuclear power's danger to health,safety,and even life itself can be summed up in one word:radia-
tion.
Nuclear radiation has a certain mystery about it,partly because it canhot be detected by human senses.
It can't be seen or heard,or touched,or tasted,even though it may be all around us.There are other
things like that.For example,radio waves are all around us but we can't detect them,sense them,without a
radio receiver. Similarly,we can't sense radioactivity without a radiation detector. But unlike common radio
waves,nuclear radiation is not harmless to human beings and other living things.
At very high levels,radiation can kill an animal or human being outright by killing masses of cells in
vital organs.But even the lowest level of radiation can do serious damage.There is no level of radiation that
is completely safe.If the radiation does not hit anything important,the damage may not be significant. This
is the case when only a few cells are hit,and if they are killed outright.Your body will replace the dead
cells with healthy ones.But if the few cells are only damaged,and if they reproduce themselves,you may be
in trouble.They reproduce themselves in a deformed way. They can grow into cancer. Sometimes this does
not show up for many years.
This is another reason for some of the mystery about nuclear radiation.Serious damage can be done
without the victim being aware at the time that damage has occurred.A person can be irradiated and feel
fine,then die of cancer five,ten,or twenty years later as a result.Or a child can be born weak or liable to
serious illness as result of radiation absorbed by its grandparents.
Radiation can hurt us.We must know the truth.

The underlined word "significant" in Paragraph 3 most probably means_________.
A:fatal
B:meaningful
C:remarkable
D:harmful