A ______ of birds flew towards us slowly from far away.A．herdB．flockC．packD．school

Passage 2
Birds are a critical part of our ecological system. But more than ever, birds are threatened byhuman pollution and climate change.
We need the birds to eat insects, move seeds and pollen around, transfer nutrients from sea toland, clean up after the mass death of the annual Pacific salmon runs, or when a wild animal fallsanywhere in a field or forest.
How could we enjoy spring without the birds flitting busily in our garden or dropping by tocheck out the flowers in our urban window box Can you contemplate America without the soaringbald eagle, or even those scavengers like the pigeons and gulls that clean up discarded food scrapson our city streets and waterfronts How diminished our lives would be without them
Scavenging eagles and condors need hunters to behave responsibly and bury, or remove, theremains of any shot deer peppered with fragments of lead bullets. Loons, ducks and other water birdswill be poisoned by lead bullets and lead fishing sinkers if we allow such objects to drop in theirfeeding space.
All sea and shore birds, even the puffins and guillemots of the otherwise pristine Aleutians,need us to make sure that no other heavy metals, like mercury and cadmium, are dumped in riversand make their way across the oceans.
Birds like the terns, knots and shearwaters that migrate between the far north and deep, deep,south of our planet need people everywhere to cease and desist from filling in their wetland fuelstops and rest stations, and from constructing golfing resorts and factories in their feeding andbreeding grounds.
Seabirds are among the most endangered vertebrate species on the planet, with the InternationalUnion for Conservation of Nature classifying 97 species as globally threatened, and 17 in the highestcategory of critically threatened. Of greatest concern are the pelicans of the southern oceans and thespectacular, but slow-breeding albatross.
Plastic bags must be eliminated from natural environments so sea and shore birds don′tmistakenly carry such debris back to feed their chicks, with invariably lethal consequences. Thealbatross, cormorants and herons need us to stop over-fishing and compromising their normal foodsupply.
The pelicans, penguins and all the birds that inhabit, or visit, our coastlines need us to ensurethat we do not dump oil into gulfs and bays, or release so much carbon dioxide into the atmospherethat the oceans turn acidic and we lose the mussels and oysters, the mass of calcareous plankton thatfeeds so many creatures, and the coral reefs that nurture enormous numbers of edible species.
Think about it: We share this small green planet. As they fly, feed and nest, the birds monitorthe health of the natural world for us, provided that we, in turn, make the effort to access that keyinformation.
The birds and humans are both large, complex and ultimately vulnerable organisms that inhabitthe top of the food chain. At the end of the day, their fate will be our fate.
Which of the following best describes the attitude

A.Humanistic.

B.Subjective.

C.Sentimental.

D.Recriminatory.

Passage 2
Birds are a critical part of our ecological system. But more than ever, birds are threatened byhuman pollution and climate change.
We need the birds to eat insects, move seeds and pollen around, transfer nutrients from sea toland, clean up after the mass death of the annual Pacific salmon runs, or when a wild animal fallsanywhere in a field or forest.
How could we enjoy spring without the birds flitting busily in our garden or dropping by tocheck out the flowers in our urban window box Can you contemplate America without the soaringbald eagle, or even those scavengers like the pigeons and gulls that clean up discarded food scrapson our city streets and waterfronts How diminished our lives would be without them
Scavenging eagles and condors need hunters to behave responsibly and bury, or remove, theremains of any shot deer peppered with fragments of lead bullets. Loons, ducks and other water birdswill be poisoned by lead bullets and lead fishing sinkers if we allow such objects to drop in theirfeeding space.
All sea and shore birds, even the puffins and guillemots of the otherwise pristine Aleutians,need us to make sure that no other heavy metals, like mercury and cadmium, are dumped in riversand make their way across the oceans.
Birds like the terns, knots and shearwaters that migrate between the far north and deep, deep,south of our planet need people everywhere to cease and desist from filling in their wetland fuelstops and rest stations, and from constructing golfing resorts and factories in their feeding andbreeding grounds.
Seabirds are among the most endangered vertebrate species on the planet, with the InternationalUnion for Conservation of Nature classifying 97 species as globally threatened, and 17 in the highestcategory of critically threatened. Of greatest concern are the pelicans of the southern oceans and thespectacular, but slow-breeding albatross.
Plastic bags must be eliminated from natural environments so sea and shore birds don′tmistakenly carry such debris back to feed their chicks, with invariably lethal consequences. Thealbatross, cormorants and herons need us to stop over-fishing and compromising their normal foodsupply.
The pelicans, penguins and all the birds that inhabit, or visit, our coastlines need us to ensurethat we do not dump oil into gulfs and bays, or release so much carbon dioxide into the atmospherethat the oceans turn acidic and we lose the mussels and oysters, the mass of calcareous plankton thatfeeds so many creatures, and the coral reefs that nurture enormous numbers of edible species.
Think about it: We share this small green planet. As they fly, feed and nest, the birds monitorthe health of the natural world for us, provided that we, in turn, make the effort to access that keyinformation.
The birds and humans are both large, complex and ultimately vulnerable organisms that inhabitthe top of the food chain. At the end of the day, their fate will be our fate.
What does the underlined word "them" in PARAGRAPH THREE refer to

A.Birds.

B.Flowers.

C.Food scrapes.

D.Scavengers.

Very few of our birds stay with us the year round.Some come to us in the winter from the cold?north.Others come from the south to spend the summer with us.How do they know the way?Suppose?you were told to find your way to a place hundreds of miles away,do you think you could do it?
Yet birds travel over mountains,forests,lakes and even across the oceans,and do not stray from?the path.They find their way back in the spring to the same orchard（果园）and the very trees where?they nested the summer before.
It is wonderful how quickly birds travel such long distances from their summer homes to their?winter ones.Some birds have been known to fly hundreds of miles in a day.But others travel much?more slowly.
Why do birds undertake these long journeys twice a year?Perhaps cold weather and lack of?food drive them from us in the autumn,but we cannot tell why they leave the sunny south to come?back to us in the spring.We know only that many of them like to make their nests and rear their?young in the north.
We are sorry to see them go,but we know that when winter is over they will come back to us.

In which season do we have most birds to stay with us?

A.In spring.
B.In summer.
C.In winter.
D.We don't know.

Very few of our birds stay with us the year round.Some come to us in the winter from the cold?north.Others come from the south to spend the summer with us.How do they know the way?Suppose?you were told to find your way to a place hundreds of miles away,do you think you could do it?
Yet birds travel over mountains,forests,lakes and even across the oceans,and do not stray from?the path.They find their way back in the spring to the same orchard（果园）and the very trees where?they nested the summer before.
It is wonderful how quickly birds travel such long distances from their summer homes to their?winter ones.Some birds have been known to fly hundreds of miles in a day.But others travel much?more slowly.
Why do birds undertake these long journeys twice a year?Perhaps cold weather and lack of?food drive them from us in the autumn,but we cannot tell why they leave the sunny south to come?back to us in the spring.We know only that many of them like to make their nests and rear their?young in the north.
We are sorry to see them go,but we know that when winter is over they will come back to us.

The underlined part"stray from the path"means__________.

A.lose its way
B.stay on the path
C.keep away from the path
D.fly along the path

Passage 2
Birds are a critical part of our ecological system. But more than ever, birds are threatened byhuman pollution and climate change.
We need the birds to eat insects, move seeds and pollen around, transfer nutrients from sea toland, clean up after the mass death of the annual Pacific salmon runs, or when a wild animal fallsanywhere in a field or forest.
How could we enjoy spring without the birds flitting busily in our garden or dropping by tocheck out the flowers in our urban window box Can you contemplate America without the soaringbald eagle, or even those scavengers like the pigeons and gulls that clean up discarded food scrapson our city streets and waterfronts How diminished our lives would be without them
Scavenging eagles and condors need hunters to behave responsibly and bury, or remove, theremains of any shot deer peppered with fragments of lead bullets. Loons, ducks and other water birdswill be poisoned by lead bullets and lead fishing sinkers if we allow such objects to drop in theirfeeding space.
All sea and shore birds, even the puffins and guillemots of the otherwise pristine Aleutians,need us to make sure that no other heavy metals, like mercury and cadmium, are dumped in riversand make their way across the oceans.
Birds like the terns, knots and shearwaters that migrate between the far north and deep, deep,south of our planet need people everywhere to cease and desist from filling in their wetland fuelstops and rest stations, and from constructing golfing resorts and factories in their feeding andbreeding grounds.
Seabirds are among the most endangered vertebrate species on the planet, with the InternationalUnion for Conservation of Nature classifying 97 species as globally threatened, and 17 in the highestcategory of critically threatened. Of greatest concern are the pelicans of the southern oceans and thespectacular, but slow-breeding albatross.
Plastic bags must be eliminated from natural environments so sea and shore birds don′tmistakenly carry such debris back to feed their chicks, with invariably lethal consequences. Thealbatross, cormorants and herons need us to stop over-fishing and compromising their normal foodsupply.
The pelicans, penguins and all the birds that inhabit, or visit, our coastlines need us to ensurethat we do not dump oil into gulfs and bays, or release so much carbon dioxide into the atmospherethat the oceans turn acidic and we lose the mussels and oysters, the mass of calcareous plankton thatfeeds so many creatures, and the coral reefs that nurture enormous numbers of edible species.
Think about it: We share this small green planet. As they fly, feed and nest, the birds monitorthe health of the natural world for us, provided that we, in turn, make the effort to access that keyinformation.
The birds and humans are both large, complex and ultimately vulnerable organisms that inhabitthe top of the food chain. At the end of the day, their fate will be our fate.
Which of the following fails to tell what birds do according to the passage

A.They help plants grow in miraculous ways.

B.They clean up the dead bodies of fish and animals.

C.They keep the oceans from being polluted and acidic.

D.They are likely to attack those irresponsible hunters.

Passage 2
Birds are a critical part of our ecological system. But more than ever, birds are threatened byhuman pollution and climate change.
We need the birds to eat insects, move seeds and pollen around, transfer nutrients from sea toland, clean up after the mass death of the annual Pacific salmon runs, or when a wild animal fallsanywhere in a field or forest.
How could we enjoy spring without the birds flitting busily in our garden or dropping by tocheck out the flowers in our urban window box Can you contemplate America without the soaringbald eagle, or even those scavengers like the pigeons and gulls that clean up discarded food scrapson our city streets and waterfronts How diminished our lives would be without them
Scavenging eagles and condors need hunters to behave responsibly and bury, or remove, theremains of any shot deer peppered with fragments of lead bullets. Loons, ducks and other water birdswill be poisoned by lead bullets and lead fishing sinkers if we allow such objects to drop in theirfeeding space.
All sea and shore birds, even the puffins and guillemots of the otherwise pristine Aleutians,need us to make sure that no other heavy metals, like mercury and cadmium, are dumped in riversand make their way across the oceans.
Birds like the terns, knots and shearwaters that migrate between the far north and deep, deep,south of our planet need people everywhere to cease and desist from filling in their wetland fuelstops and rest stations, and from constructing golfing resorts and factories in their feeding andbreeding grounds.
Seabirds are among the most endangered vertebrate species on the planet, with the InternationalUnion for Conservation of Nature classifying 97 species as globally threatened, and 17 in the highestcategory of critically threatened. Of greatest concern are the pelicans of the southern oceans and thespectacular, but slow-breeding albatross.
Plastic bags must be eliminated from natural environments so sea and shore birds don′tmistakenly carry such debris back to feed their chicks, with invariably lethal consequences. Thealbatross, cormorants and herons need us to stop over-fishing and compromising their normal foodsupply.
The pelicans, penguins and all the birds that inhabit, or visit, our coastlines need us to ensurethat we do not dump oil into gulfs and bays, or release so much carbon dioxide into the atmospherethat the oceans turn acidic and we lose the mussels and oysters, the mass of calcareous plankton thatfeeds so many creatures, and the coral reefs that nurture enormous numbers of edible species.
Think about it: We share this small green planet. As they fly, feed and nest, the birds monitorthe health of the natural world for us, provided that we, in turn, make the effort to access that keyinformation.
The birds and humans are both large, complex and ultimately vulnerable organisms that inhabitthe top of the food chain. At the end of the day, their fate will be our fate.
What does the author intend to do in writing the passage

A.To evaluate our needs of birds to save our earth.

B.To describe various measures to protect the birds.

C.To criticize the effects of human pollution on birds.

D.To explain a basic tie between birds and human beings.

Very few of our birds stay with us the year round.Some come to us in the winter from the cold?north.Others come from the south to spend the summer with us.How do they know the way?Suppose?you were told to find your way to a place hundreds of miles away,do you think you could do it?
Yet birds travel over mountains,forests,lakes and even across the oceans,and do not stray from?the path.They find their way back in the spring to the same orchard（果园）and the very trees where?they nested the summer before.
It is wonderful how quickly birds travel such long distances from their summer homes to their?winter ones.Some birds have been known to fly hundreds of miles in a day.But others travel much?more slowly.
Why do birds undertake these long journeys twice a year?Perhaps cold weather and lack of?food drive them from us in the autumn,but we cannot tell why they leave the sunny south to come?back to us in the spring.We know only that many of them like to make their nests and rear their?young in the north.
We are sorry to see them go,but we know that when winter is over they will come back to us.

How far do birds usually travel from their summer homes to their winter ones?

A.About hundreds of miles.
B.About thousands of miles.
C.The distance that takes a bird to fly the whole morning.
D.The passage does not tell us.

Very few of our birds stay with us the year round.Some come to us in the winter from the cold?north.Others come from the south to spend the summer with us.How do they know the way?Suppose?you were told to find your way to a place hundreds of miles away,do you think you could do it?
Yet birds travel over mountains,forests,lakes and even across the oceans,and do not stray from?the path.They find their way back in the spring to the same orchard（果园）and the very trees where?they nested the summer before.
It is wonderful how quickly birds travel such long distances from their summer homes to their?winter ones.Some birds have been known to fly hundreds of miles in a day.But others travel much?more slowly.
Why do birds undertake these long journeys twice a year?Perhaps cold weather and lack of?food drive them from us in the autumn,but we cannot tell why they leave the sunny south to come?back to us in the spring.We know only that many of them like to make their nests and rear their?young in the north.
We are sorry to see them go,but we know that when winter is over they will come back to us.

Why do birds undertake those long journeys twice a year?

A.It is because of cold weather in winter.
B.It is because of lack of food in autumn.
C.It is because of the hot weather in summer.
D.There's some reason that is still not known clearly.