--- You look ______,Paul. What’s the matter?--- I’m having trouble ______ math.
The money will be used to help the people____1ost their homes in the Tsunami(海啸).
The boy___ streets without pay in the old days.
— How do you improve your writing skills?—_________ .
I have spent______ on this job. I think I can finish it______this afternoon.
Boy, didn’t you see people were waiting in line? Don’t______in!