Would you like to help clean up the school yard—_______. But I’m busy now.

members of a team perform better, the trainer first of all has to knowtheir ______ and weaknesses

Nowadays people seem to be becoming more and more selfish.— How much better life would be if we ______ to the values of the past!

My mother was making dinner I was doing homework.

下列各句中，加横线的成语使用恰当的一项是（ ）