—If you're free tonight, I'd like to invite you to a movie.—That's nice of you, but are you________?
The fact that people are afraid to go out at night is often a result of perceived (感知) danger ________actual danger.
Mother told Jim to watch the milk until it boiled and then _________ off the gas.
The idea puzzled me so much that I stopped for a few seconds to try to _______.
With exports ______ a big role in its economic growth, China has been affected by the current financial storm.
— How about buying Sam a mobile phone? After all, he isn’t a boy any more. —I think it necessary, for we sometimes want to make sure if he _______ home for dinner.