5.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 (懸崖) and deep valleys were formed from thick mud that once lay under 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.
28.Many plants may survive in deserts whenD.
A.it is dry all the year round
B.the rain falls only in a few weeks
C.there is little rain in a year
D.the rain is spread out in a year
29.Sand dunes are formed whenA.
A.sand piles up little by little
B.there is plenty of rain in a year
C.the sea has dried up over the years
D.pieces of rock get smaller
30.The underlined sentence in the third paragraph probably means that in a desert there isD.
A.too much sand
B.more sand than before
C.nothing except sand
D.something else besides sand
31.It can be learned from the text that in a desertB.
A.there is no rainfall throughout the year
B.life exists in rough conditions
C.a(chǎn)ll sand dunes are a few feet high
D.rocks are worn away only by wind and heat.
分析 本文是一篇廣告布告類閱讀,文章主要介紹了沙漠的形成,沙漠上的景觀和生命等情況.此外,還對沙漠的自然狀況以及沙漠的形成、植被、氣候特征等進行了介紹.
解答 DADB
28.D 事實細節(jié)題.根據(jù)第一段第二句"…for many plants to survive if the rain is spread throughout the year",如果一年降雨量是10英寸,且降雨分布在全年,那么許多植物就可以生存.throughout the year意思是"全年"或"一年中".與B項中plenty of rain in a year同義,故選D.
29.A 事實細節(jié)題,根據(jù)第二段第二句和第三句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."當(dāng)風(fēng)吹動沙子穿過沙漠、沙丘就形成了.一點一點沙丘會經(jīng)過幾年而增大",而A項piles up gradually為"逐漸堆積起來"之意.故選A.
30.D 句義猜測題.劃線句子意思是"可是,對于沙漠來說,有的不僅僅是沙子"也就是說除了沙子還有其它的自然界的東西讓沙漠發(fā)生變化,并且本段有所描述.故選D.
31.B 推理判斷題.根據(jù)最后一段Most deserts have a surprising variety of life.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.在最后一段中文章描述到"大多數(shù)沙漠都生有讓人驚嘆的生命,在白天,觀光者能夠看到很少的生命體,白天一片沉寂與荒涼,只有到晚上,沙漠才有了生機",故選B.
點評 本文考察學(xué)生的理解推斷能力以及細心程度,只要抓住文章的關(guān)鍵詞,采用尋讀的方法查找細節(jié),就能找到正確答案.