I’m afraid I’ll spend _____ two hours _______on the problem.

There is ______ American boy in our class and ______ boy can speak good Chinese .

What do you think we can do for our aged parents—You ____ do anything except to be with them and be yourself.

We delayed our departure ___ the bad weather

to feel very nervous when I stood up in frontof others, but now I feel quite ______when giving a speech to the school．