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

C. nothing except sand B. more sand than before 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

解析:

60．A 解析：事实细节题，根据第一段第二句“ for many plants to survive if the

rain is spread throughout the year”，throughout the year意思是“全年”或“一年