Bats(蝙蝠) are the only flying “animals” in the world.
It is known to all that they cannot see very well. “As b____________________(88) as a bat” is often h____________________(89).
Yet they have no trouble flying on the d____________________ (90) nights and finding their way r____________________ (91) very well. Why can bats fly and see at night? They fly by “radar(雷达)”. The bat's radar w____________________ (92)
the same way as the radar on ships and planes. As a bat flies t____________________ (93) the air, it makes a sound. If the sounds hit t____________________(94), they will come back and the bat's e____________________(95) will receive the message. In this way, the bat is a____________________(96) to know where the things are. Bats go out for f____________________(97) at night. In the daytime, they hang in some dark places.