—Professor, do you have something _______ at this moment?— No, thanks. I’ll call you if any.
Excuse me, but can you tell me _____?
_____ he said is really interesting.
Mary often helps her best friend, ______ math is very poor.
Beijing is _____ capital of _____ China.
To be able to catch up with the other students, he needs ___ hard work; he needs your encouragement, too.