18.As they migrate(遷移),butterflies and moths choose the winds they want to fly with,and they change their body positions if they start floating in the wrong direction.This new finding suggests that insects may employ some of the same methods that birds use for traveling long distances.Scientists have long thought that insects were simply at the mercy of the wind.
Fascinating as their skills of flight are,migrating behavior has been difficult to study in.insects because many long distant trips happen thousands thousands of feet above ground. Only recently i have scientists developed technologies that can detect such little creatures at such great heights.
To their surpri se,though,the insects weren't passive travelers on the winds.In autumn,for example,most light winds blew from the east,but the insects somehow sought out ones that carried them south and they positioned themselves to navigate directly to their wIntenng homes.
Even in the spring,when most winds flowed northward,the insects didn't always go with the flow.If breezes weren't blowing in the exact direction they wanted to go,the insects changed their body positions to compensate.Many migrating birds do the same thing.
The study also found,butterflies and moths actively flew within the air streams that pushed them along.By adding flight speeds to wind speeds,the scientists calculated that butterflies and moths can travel as fast as 100 kilometers an hour.The findings may have real-world applications.
With climate warming,migrating insects are growing in number.Knowing how and when these pests move could help when farmers decide when to spray their crops.
71.Whatl S the main idea of the text?C
A.Insects migrate with the seasons.
B.Wind helps insects greatly in migrating.
C.Windsurfing insects have real direction.
D.Scientists have trouble in observing insects.
72.Scientists originally thought thatC.
A.insects always waited for their favourable winds
B.insects chose the winds they wanted to ride
C.insects were j ust blown about by the wind
D.insects posi tioned themselves in the winds
73.It is not easy to stuay the migrating behavior of the insects becauseD
A.the little creatures can fly very fast
B.they have no regular migrating courses
C.the wind's direction is hard to f.oresee
D.their flight is long and high above ground
74.We can learn from the text thatA
A.insects fly in the way birds do
B•insects travel more easily in autumn
C.insects never position themselves when flying low
D.insects rest a lot when the wind pushes them along
75.According to the passage,the findings canB.
A.increase insects in number B.instruct farmers when to spray
C.prevent climate warming D.help protect insects.
分析 本文是一篇科教類閱讀,主要講述了帆板類昆蟲也有真正的方向.
解答 71-75.CCDAB
71題答案:C考查主旨大意,本文主要講了實(shí)際上帆板類昆蟲其實(shí)也是有方向的,而不是像人們以為的任由風(fēng)擺布;故本題答案為C選項(xiàng).
72題答案:C考查細(xì)節(jié)推理,根據(jù)原文第二段的最后一句Scientists have long thought that insects were simply at the mercy of the wind.科學(xué)家長期以來一直以為昆蟲只是任由風(fēng)擺布.可知本題答案為C選項(xiàng).
73題答案:D考查細(xì)節(jié)推理,根據(jù)原文的 because many long distant trips happen thousands thousands of feet above ground.因?yàn)楹芏嚅L距離的旅行發(fā)生在距離地面數(shù)以千計(jì)英尺的高空.可知本題答案為D選項(xiàng).
74題答案:A考查細(xì)節(jié)推理,根據(jù)文章首段的This new finding suggests that insects may employ some of the same methods that birds use for traveling long distances.該項(xiàng)新的發(fā)現(xiàn)表明昆蟲可能運(yùn)用了鳥類遠(yuǎn)距離飛行的某些方法.可知本題答案為A選項(xiàng).
75題答案:B考查細(xì)節(jié)推理,根據(jù)文章最后一段的Knowing how and when these pests move could help when farmers decide when to spray their crops.知道這些昆蟲是如何及何時(shí)移動(dòng)(遷徙)能夠幫助農(nóng)民決定何時(shí)澆灌莊稼.故本題答案為B選項(xiàng).
點(diǎn)評(píng) 本文是一篇科教類閱讀,題目涉及多道細(xì)節(jié)理解題,做題時(shí)結(jié)合原文和題目有針對(duì) 性找出相關(guān)語句進(jìn)行仔細(xì)分析,結(jié)合選項(xiàng)選出正確答案.推理判斷也是要在抓住關(guān)鍵句子的基礎(chǔ)上合理的分析才能得出正確的答案.