四六级考试阅读的备考笔记参考

Of course, the bats have had some 50 million years of evolution to refine their sonar. Their physiological mechanisms for echo location, based on all this accumulated experience, therefore deserve our thorough study and analysis.

注：ne 提炼、改善

2.二段首句是对首段末句的解释

3.50 million years对应的是第17小题

17. The author suggests that the sonar system of bats ____

A) was at the height of its perfection 50 million years ago

B) is better than man-made sonar because it has had 50 million years to be be refined

C) should have been discovered by man many years ago

D) is the same as it was 50 million years ago

注：B 选项体现一段结尾和二段开头，应该优选，含有关系词 because,although,not also, as well as 的应该优选

To appreciate the precision of the bats echo location, we must first consider the degree of their reliance upon it. Thanks to sonar, an insect-eating bat can get along perfectly well without eyesight. This was brilliantly demonstrated by the Italian naturalist Lazzaro Spallanzani. He caught some bats in a bell tower, blinded them and released them outdoors. Four of these blind bats were recaptured after they had found their ways back to the bell tower, and on examining their stomachs contents, Spallanxani found that they had been able to capture and eat flying insects. We know from experiments that bats easily find insects in the dark of night, even when the insects make no sound that can be heard by human ears. A bat will catch hundreds of softbodied silent flying insects in a single hour. It will even detect and chase pebbles tossed this is the age of technological triumphs