The president was so absorbed in his work that not a sound _____.
--I’m sorry, but I didn’t mean ______ out your secret. --But you know, letting out one’s secret means ______ one’s feeling.
The boys were playing football on the ground. Sandy didn’t want to ______ them.
Finding information on the Internet is easy. The ______ is how you can tell whether the information is useful or not.
You’d better have your room ______. It’s ______.
The condition prevents the blood from freely.