选用方框内所给词的适当形式填空。每个词只能用一次。

Play  easy  polite  animal   work

 
My brother is very busy. He often ________  day and night.
—What do you think of this math problem?
—It’s as    as anything.
“May I come in?” he asked      .
Mrs. Black doesn’t allow her son       computer games on school nights.
We should be friendly to     . They’re also members of our world.