Doctors are doing research to find out what happens physically when people ______ smoking.

Which would you like, coffeetea?—Teamilk, please. [ ]

Smoking is not allowed in public places since May 1st. It may be a good chance for some people to ______ smoking.

_______ bike is next to my car? — Oh, it’s Sonia’s, it’s a nice one.

I found ___________ hard to remember all the twelve star signs because they are difficult to pronounce(发音) and spell.