10.There are desert plants which survive the dry season in the form of inactive seeds.There are also desert insects which survive as inactive larvae (幼蟲(chóng)).In addition,difficult as it is to believe,there are desert fish which can survive through years of drought (干旱) in the form of inactive eggs.These are the shrimps (蝦) that live in the Mojave Desert,an extremely dry place in the southwest of the United States where shade temperatures of over 50℃are often recorded.
The eggs of the Mojave shrimps look like grains of sand both in size and appearance.When enough spring rain falls to form a lake,once every two to five years,these eggs hatch.Then the water is soon filled with millions of tiny shrimps about a millimeter long which feed on tiny plant and animal organisms (有機(jī)物)which also grow in the temporary desert lake.Within a week,the shrimps grow from their original 1millimeter to a length of about 1.5centimeters.
Throughout the time that the shrimps are rapidly maturing,the water in the lake equally rapidly evaporates(蒸發(fā)).Therefore,for the shrimps it is a race against time.By the 12th day,however,when they are about 3centimeters long,hundreds of tiny eggs form on the underbodies of the females.Usually by this time,all that remains of the lake is a large,muddy patch of wet soil.On the 13th day,the shrimps lay their eggs in the mud.Then,having ensured that their species will survive,the shrimps die as the last of the water evaporates.
If enough rain falls the next year to form another lake,the eggs hatch,and once again the shrimps pass rapidly through their cycle of growth,adulthood,egg-laying,and death.Some years there is not enough rain to form a lake:in this case,the eggs will remain dormant for another year,or even longer if necessary.
28.Which of the following is the MOST unique feature of Mojave shrimps?C
A.Their lives are brief.
B.They feed on plant and animal organisms.
C.Their eggs can survive years of drought.
D.They lay their eggs in the mud.
29.What does the underlined word"dormant"in the last paragraph most probably mean?A
A.Inactive.
B.Sleeping.
C.Safe.
D.Dead.
30.What can be inferred from the passage?D
A.Appearance and size are the most important for life to survive in the desert.
B.A species must be able to grow up quickly in order to survive.
C.Shrimps are the only species with a life cycle of 13days.
D.Some species develop a unique life pattern to survive in extremely hard condition.
31.What is the passage mainly about?B
A.The life span of Mojave shrimps
B.The survival of desert shrimps
C.The creatures living in the Mojave desert
D.The importance of water to life in the desert.
分析 本文屬于說(shuō)明文閱讀,作者通過(guò)這篇文章向我們介紹了一些物種在極端艱苦的環(huán)境中形成了獨(dú)特的生存模式,這使他們能生存下來(lái).
解答 28.C 推理判斷題,根據(jù)第一段In addition,difficult as it is to believe,there are desert fish which can survive through years of drought (干旱) in the form of inactive eggs.可知莫哈韋沙漠蝦的蛋能在多年的干旱中存活,故選C.
29.A 詞義猜測(cè)題,根據(jù)最后一段Some years there is not enough rain to form a lake:in this case,the eggs will remain dormant for another year,or even longer if necessary.可知如果沒(méi)有足夠的雨水,這些蛋會(huì)不活動(dòng),保持蟄伏的狀態(tài),故選A.
30.D 推理判斷題,通讀全文可知這篇文章向我們介紹了一些物種在極端艱苦的環(huán)境中形成了獨(dú)特的生存模式,故選D.
31.B 主旨大意題,通讀全文可知作者通過(guò)這篇文章向我們介紹了沙漠蝦的生存特征,故選B.
點(diǎn)評(píng) 考查學(xué)生的細(xì)節(jié)理解和推理判斷能力.做細(xì)節(jié)理解題時(shí)一定要找到文章中的原句,和題干進(jìn)行比較,再做出正確選擇.在做推理判斷題時(shí)不要以個(gè)人的主觀想象代替文章的事實(shí),要根據(jù)文章事實(shí)進(jìn)行合乎邏輯的推理判斷.