20、Bats are the only flying mammals（哺乳动物）in the world．They can’t see very well，but people believe they have no trouble（干某事不困难）flying on darkest nights and finding their way around very well．How can bats fly（飞）and see at night? They fly by radar（雷达）．

The bat’s radar system（系统）works the same as ships and planes do．As a bat flies through the air，he makes a sound（声音）．The sound is high enough for his message．In this way it tells the bat where the thing is．

Bats go out to look for food only at night．In the daytime（白天）they rest in some dark places．

1．The bat is ________ in Chinese．

A．蝙蝠                      B．老鼠                       C．蚊子                      D．蜻蜓

2．The bat has no trouble flying on the darkest nights because ________．

A．its eyes are good                                         B．it can’t see well

C．it can make a sound                                   D．it has a kind of radar system to help it

3．When does the bat begin to go out to look for food?

A．In the daytime．                                         B．In the early morning．

C．When night comes．                                  D．In the late afternoon．

4．The bat“sees”things with its ________．

A．eyes                       B．nose                       C．mouse                   D．ears

5．Which of the following is right?

A．The bat is the only flying animal in the world．

B．The bat is blind，but it can“see”its food．

C．Not all bats are afraid of flying in the sun．

D．The bat often comes out during daytime，too．