Being honest is the first _____________ if you want to make friends with others.
I'm surprised to hear from her. ________, we last met ten years ago.
Thanks to the Internet, different kinds of information ________ in a short time.
-- Our school bus will leave at 8 o'clock tomorrow. Don't be late.-- OK. I will be there ten minutes________.
The rivers will become dirtier and dirtier ______ we take action to protect them.
He is an honest boy. I have no reason to _______ what he said.