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.
68. 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
69. 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
70. 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
71. 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

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.

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

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

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

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

单词拼写(共10小题；每小题1分，满分l0分)

1．Please keep me_____通知)of what happens．

2．_______(显然), what he said has nothing to do with me．

3．Years ago，my daughter_______ (更喜欢) apples to bananas

4．The old professor joined a_______( 医疗) team and went to the flooded areas．

5．If the rain_____ (连续) for a few more days, our crops will be mined．

6．The _____ （熟悉的）face suggested that I must have seen him before．

7．We are both newcomers. Do you have any friends or _____（亲戚） here?

8．I received a letter ________ （邀请）me to a national English teaching conference．

9．As is well known to us all, the ______  （十二）month of a year is called December

10．On hearing the news, he went to the hospital to see his friend without ____（拖延）

If the rain ________, we’ll have to change tonight’s plan．

1. A.
   goes
2. B.
   stays
3. C.
   continues
4. D.
   keeps

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.