难度:★★★★ 考点:完形填空
Bats(蝙蝠) are the only mammals(哺乳动物) is the world. They can't _1_ very well. It was long believed, and still is in many places, that all bats are blind. "Blind as a bat" is often heard. Yet they have no trouble _2_ on the darkest nights and finding their way _3_ very well. How can bats fly and see at night? They fly by radar(雷达)!
The bat's radar system works like the one on a ship or a plane. As a bat flies through the air, he makes a _4_ that is too high, for our ears to hear. If the sounds _5_ things, they come back. The bat's ears receive the _6_ . In this way they are able to tell the bat _7_ the things are.
Bats go out to look _8_ food at night. In the day-time they _9_ in some dark places. Some people have bats as bad animals. In _10_ , they are useful animals.
1.A. look B. see C. hear D.find
2.A.flying B.running C.jumping D.walking
3.A.off B.up C.over D.around
4.A.cry B.sound C.voice D.noise
5.A.hit B.meet C.shake D.get
6.A.knowledge B.advice C.words D.message
7.A.which B.whether C.where D.when
8.A.up B.at C.for D.after
9.A.hang B.come C.fly D.move
10.A.result B.fact C.return D.home