Why is he feeling down today—Because the suggestion he________has beenturned down.

It’s helpful to put students in a situation _______ theycan learn how to cooperate with each other.

I stayed in Japan only a few matches,, I went through a series of hardship.

of the waste thrown away in the U.S. __________ being shipped overseas to China, India, and other developing countries.

Will you go to Hangzhou by _____ car —No, I’ll take _____ train.