用所给词组的适当形式填空。（5分）

be able to     hear of     keep…down    fall in love     pick up

小题1:Have you ever __________ __________ Donald Duck?
小题2:She’s doing her homework. Would you mind _________ your voice_________?
小题3:We often see the boy __________ __________ the litter in the school yard.
小题4:He _________ __________ __________ drive a car when he was 18.
小题5:Last summer Lisa went to Guilin. She __________ __________ __________ with it.