矫治大的邻牙间隙(black space)可以采用的方法是A.直接固定矫治器关闭间隙 B.邻面去釉后关闭间隙 C.调节相邻牙轴倾度 D.正位器 E.活动矫治器

共用题干
Black Holes

Most scientists agree that black holes exist but are nearly impossible to locate.A black
hole in the universe is not a solid object,like a planet,but it is shaped like a sphere（球体）.
Astronomers（天文学家）think that at the center of a black hole there is a single point in
space with infinite（无限的）density（稠密）.This single point is called a singularity（奇点）.
If the singularity theory is correct,it means that when a massive star collapses,all the
material in it disappears into the singularity.The center of a black hole would not really be a
hole at all,but an infinitely dense point.Anything that crosses the black hole is pulled in by
its great gravity.
Although black holes do exist,they are difficult to observe.These are the reasons.
No light or anything else comes out of black holes.As a result,they are invisible to
a telescope.
In astronomical terms,black holes are truly tiny.For example,a black hole formed
by the collapse of a giant star would have an event horizon（视界）only 18 miles across.
The nearest black holes would be dozens of light years away from Earth.One light
year is about 6 trillion（万亿）miles. Even the most powerlul telescopes could not pick out
an object so small at such a great distance.
In 1994 the Hubble Space Telescope provided evidence that black holes exist.There
are still answers to be found,however,so black holes remain one of the mysteries of the
universe.

The sun is the heaviest star in the universe.
A:Right
B:Wrong
C:Not mentioned

共用题干
Black Holes

Most scientists agree that black holes exist but are nearly impossible to locate.A black
hole in the universe is not a solid object,like a planet,but it is shaped like a sphere（球体）.
Astronomers（天文学家）think that at the center of a black hole there is a single point in
space with infinite（无限的）density（稠密）.This single point is called a singularity（奇点）.
If the singularity theory is correct,it means that when a massive star collapses,all the
material in it disappears into the singularity.The center of a black hole would not really be a
hole at all,but an infinitely dense point.Anything that crosses the black hole is pulled in by
its great gravity.
Although black holes do exist,they are difficult to observe.These are the reasons.
No light or anything else comes out of black holes.As a result,they are invisible to
a telescope.
In astronomical terms,black holes are truly tiny.For example,a black hole formed
by the collapse of a giant star would have an event horizon（视界）only 18 miles across.
The nearest black holes would be dozens of light years away from Earth.One light
year is about 6 trillion（万亿）miles. Even the most powerlul telescopes could not pick out
an object so small at such a great distance.
In 1994 the Hubble Space Telescope provided evidence that black holes exist.There
are still answers to be found,however,so black holes remain one of the mysteries of the
universe.

Black holes are part of space.
A:Right
B:Wrong
C:Not mentioned

牙间隙增大时用于清洁邻面和根分叉区的是

A．刷牙
B．牙线
C．牙签
D．牙间隙刷
E．龈上洁治术

牙周病正畸中不适宜的操作方法是

A.及时调，去除咬合创伤
B.采用对称性拔牙矫治
C.采用牙弓分段排齐
D.采用邻面去釉方法
E.必要时进行牙齿去髓磨改，减小冠根比

共用题干
Black Holes

Most scientists agree that black holes exist but are nearly impossible to locate.A black
hole in the universe is not a solid object,like a planet,but it is shaped like a sphere（球体）.
Astronomers（天文学家）think that at the center of a black hole there is a single point in
space with infinite（无限的）density（稠密）.This single point is called a singularity（奇点）.
If the singularity theory is correct,it means that when a massive star collapses,all the
material in it disappears into the singularity.The center of a black hole would not really be a
hole at all,but an infinitely dense point.Anything that crosses the black hole is pulled in by
its great gravity.
Although black holes do exist,they are difficult to observe.These are the reasons.
No light or anything else comes out of black holes.As a result,they are invisible to
a telescope.
In astronomical terms,black holes are truly tiny.For example,a black hole formed
by the collapse of a giant star would have an event horizon（视界）only 18 miles across.
The nearest black holes would be dozens of light years away from Earth.One light
year is about 6 trillion（万亿）miles. Even the most powerlul telescopes could not pick out
an object so small at such a great distance.
In 1994 the Hubble Space Telescope provided evidence that black holes exist.There
are still answers to be found,however,so black holes remain one of the mysteries of the
universe.

The nearest black holes are hundreds of light years away from us.
A:Right
B:Wrong
C:Not mentioned

共用题干
Black Holes

Most scientists agree that black holes exist but are nearly impossible to locate.A black
hole in the universe is not a solid object,like a planet,but it is shaped like a sphere（球体）.
Astronomers（天文学家）think that at the center of a black hole there is a single point in
space with infinite（无限的）density（稠密）.This single point is called a singularity（奇点）.
If the singularity theory is correct,it means that when a massive star collapses,all the
material in it disappears into the singularity.The center of a black hole would not really be a
hole at all,but an infinitely dense point.Anything that crosses the black hole is pulled in by
its great gravity.
Although black holes do exist,they are difficult to observe.These are the reasons.
No light or anything else comes out of black holes.As a result,they are invisible to
a telescope.
In astronomical terms,black holes are truly tiny.For example,a black hole formed
by the collapse of a giant star would have an event horizon（视界）only 18 miles across.
The nearest black holes would be dozens of light years away from Earth.One light
year is about 6 trillion（万亿）miles. Even the most powerlul telescopes could not pick out
an object so small at such a great distance.
In 1994 the Hubble Space Telescope provided evidence that black holes exist.There
are still answers to be found,however,so black holes remain one of the mysteries of the
universe.

The Hubble Space Telescope helps scientists to understand the nature of the universe.
A:Right
B:Wrong
C:Not mentioned

以下描述错误的是

A.修复前对错位牙使用牙少量移动的矫治技术，能改善修复的效果
B.对残根缺损达龈下的患牙，可以考虑用矫治的方法将其牵出
C.牙列缺损并且有上前牙间隙的病例，可先将间隙关闭后再修复
D.对进行性牙周炎患者，可用矫治技术解决牙周病造成的牙齿移位
E.正确使用牙少量移动的矫治技术可以获得良好的效果

大的邻牙间隙(blackspace)可以通过以下哪种方法矫治

A.直接固定矫治器关闭间隙
B.正位器
C.活动矫治器
D.调节相邻牙轴倾度
E.邻面去釉后关闭间隙

矫治大的邻牙间隙(black space)可以采用的方法是

A.直接固定矫治器关闭间隙
B.邻面去釉后关闭间隙
C.调节相邻牙轴倾度
D.正位器
E.活动矫治器