As the air is being polluted.many kinds of wild animals are .A.diedB.dying downC.dying outD.death 题目和参考答案——青夏教育精英家教网—

Deserts are found where there is little rainfall or where rain for a whole year falls in only a few weeks’ time. Ten inches of rain may be enough for many plants to survive （存活）if the rain is spread throughout the year, If it falls, within one or two months and the rest of the year is dry, those plants may die and a desert may form.

Sand begins as tiny pieces of rock that get smaller and smaller as wind and weather wear them down. Sand dunes （沙丘） are formed as winds move the sand across the desert. Bit by bit, the dunes grow over the years, always moving with the winds and changing the shape. Most of them are only a few feet tall, but they can grow to be several hundred feet high.

There is, however, much more to a desert than sand. In the deserts of the southwestern United States, cliffs （悬崖） and deep valleys were formed from thick mud that once lay beneath a sea more than millions of years ago. Over the centuries, the water dried up. Wind, sand, rain, heat and cold all wore away at the remaining rocks. The faces of the desert mountains are always changing – very, very slowly – as these forces of nature continue to work on the rock.

Most deserts have a surprising variety of life. There are plants, animals and insects that have adapted to life in the desert. During the heat of the day, a visitor may see very few signs of living things, but as the air begins to cool in the evening, the desert comes to life. As the sun begins to rise again in the sky, the desert once again becomes quiet and lonely.

60. Many plants may survive in deserts when__________________.

A. the rain is spread out in a year B. the rain falls only in a few weeks

C. there is little rain in a year D. it is dry all the year round

61. Sand dunes are formed when___________________.

A. sand piles up gradually B. there is plenty of rain in a year

C. the sea has dried up over the years D. pieces of rock get smaller

62. The underlined sentence in the third paragraph probably means that in a desert there is____________.

A. too much sand B. more sand than before

C. nothing except sand D. something else besides sand

63 It can be learned from the text that in a desert ____________.

A. there is no rainfall throughout the year B. life exists in rough conditions

C. all sand dunes are a few feet high D. rocks are worn away only by wind and heat

The Peppered Moth, a kind of insect(昆虫), is found in England. It is light brown in colour and likes to settle(栖息) on trees which are also light brown. This makes the moth difficult to be seen and birds are less likely to notice and eat it.
But with the development of industry(工业) , smoke from factories began to reach the trees where the moth settled. It made the trees blacker. Then something very strange took place: in industrial areas, the Peppered Moth began to change colour. It became darker as well. Though the change took several years, some scientists soon notice that newly-born moths were a little darker than usual.
A scientist with the name Kettlewell decided to make a careful study of this phenomenon(现象). He marked some of the light moths and some of the darker ones, and set them free in the woods near Bermingham, an industrial city. Later, he recaptured(重新捕获) as many as the marked moths as possible. The results were as follows.

	light moths	darker moths
Moths set free	201	601
moths recaptured	34(16%)	206(34%)

Kettlewell's research (研究) was done in the early 1950s. Soon afterwards Britain introduced new laws to reduce smoke and factory pollution.
Can you imagine what would happen to the Peppered Moth as the air became cleaner again?
【小题1】The Peppered Moth began to change its colour in industrial areas because .

A．it itself liked to

B．it could be like the colour of its living-place

C．it had to keep the balance of nature

D．it was usually dark brown

【小题2】From the results of Kettlewell's research, we can see that .

A．many more of the light moths were killed or eaten

B．more than one-fifth of the light moths was not killed

C．three times as many dark moths were kept safe as light ones

D．more dark moths were killed in industrial areas

【小题3】As the air became cleaner, .

A．the number of the light moths became larger

B．the total number of the light moths remained unchanged

C．there were more of the darker moths and fewer of the light ones

D．the darker moths changed into the light ones suddenly

Deserts are found where there is little rainfall or where rain for a whole year falls in only a few weeks' time. Ten inches of rain may be enough for many plants to survive (存活) if the rain is spread throughout the year. If it falls within one or two months and the rest of the year is dry, those plants may die and a desert may form.

Sand begins as tiny pieces of rock that get smaller and smaller as wind and weather wear them down. Sand dunes (沙丘) are formed as winds move the sand across the desert. Bit by bit, the dunes grow over the years, always moving with the winds and changing the shape. Most of them are only a few feet tall, but they can grow to be several hundred feet high.

There is, however, much more to a desert than sand. In the deserts of the southwestern United States, cliffs (悬崖) and deep valleys were formed from thick mud that once lay beneath a sea more than millions of years ago. Over the centuries, the water dried up. Wind, sand, rain, heat and cold all wore away at the remaining rocks. The faces of the desert mountains are always changing--very, very slowly--as these forces of nature continue to work on the rock.

Most deserts have a surprising variety of life. There are plants, animals and insects that have adapted to life in the desert. During the heat of the day, a visitor may see very few signs of living things, but as the air begins to cool in the evening, the desert comes to life. As the sun begins to rise again in the sky, the desert once again becomes quiet and lonely.

1.Many plants may survive in deserts when_______.

A．the rain falls only in a few weeks

B．the rain is spread out in a year

C．there is little rain in a year

D．it is dry all the year round .

2.Sand dunes are formed when_______.

A．there is plenty of rain in a year

B．sand piles up gradually

C．the sea has dried up over the years

D．pieces of rock get smaller

3.The underlined sentence in the third paragraph probably means that in a desert there is_______.

A．too much sand B．more sand than before

C．nothing except sand D．something else besides sand

4.It can be learned from the text that in a desert_______.

A．there is no rainfall throughout the year

B．life exists in rough conditions

C．all sand dunes are a few feet high

D．rocks are worn away only by wind and heat

5.What’ the best title of this passage?

A．Deserts. B．The plants in the deserts.

C．The rainfall in the deserts. D．Sand dunes.

选择正确词组（每小题1分，共6分）

care about as usual be fond of at an end go through in ruins

at present because of graduate from get along with give in

Be concerned about think well of

温馨提示：注意词型的适当变化

1. After ________the university, he was employed by an oversea company.

2. It seemed that the whole city lay _________after the flood.

3. _________he hurried his breakfast and washed the smelly clothes.

4. I like swimming while my son __________playing with toy blocks

5. I have made it clear that I will never________ to anybody.

6. I don’t ________the price, so long as the air-conditioner is of fine quality.

Deserts are found where there is little rainfall or where rain for a whole year falls in only a few weeks’ time. Ten inches of rain may be enough for many plants to survive if the rain is spread throughout the year. If it falls within one or two months and the rest of the year is dry, those plants may die and a desert may form.

Sand begins as tiny pieces of rock that get smaller and smaller as wind and weather wear them down. Sand dunes（沙丘）are formed as winds move the sand across the desert. Bit by bit, the dunes grow over the years, always moving with the winds and changing the shape. Most of them are only a few feet tall, but they can grow to be several hundred feet high.

There is, however, much more to a desert than sand. In the deserts of the southwestern United States, cliffs（悬崖）and deep valleys were formed from thick mud that once lay beneath a sea more than millions of years ago. Over the centuries, the water dried up. Wind, sand, rain, heat and cold all wore away at the remaining rocks. The faces of the desert mountains are always changing—very, very slowly—as these forces of nature continue to work on the rock.

Most deserts have a surprising variety of life. There are plants, animals and insects that have adapted to life in the desert. During the heat of the day, a visitor may see very few signs of living things, but as the air begins to cool in the evening, the desert comes to life. As the sun begins to rise again in the sky, the desert once again becomes quiet and lonely.

1.Many plants may survive in deserts when ________.

A．the rain is spread out in a year B．the rain falls only in a few weeks

C．there is little rain in a year D．it is dry all the year round

2.Sand dunes are formed when _______.

A．sand piles up gradually B．there is plenty of rain in a year

C．the sea has dried up over the years D．pieces of rock get smaller

3.The underlined sentence in the third paragraph probably means that in a desert there is ______.

A．too much sand B．more sand than before

C．nothing except sand D．something else besides sand

4.It can be learned from the text that in a desert _______.

A．there is no rainfall throughout the year

B．life exists in rough conditions

C．all sand dunes are a few feet high

D．rocks are worn away only by wind and heat

As the air is being polluted，many kinds of wild animals are________.

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