---How much money did you pay for the drink?---None. It’s ______.

I think math is not ________ science.

—You see, “Food Safety” receives thousands of Internet hits a day.—Obviously, it has become one of the________ topics recently.

–That clothes store is ________ on weekends.--I see. I’ll go there next Monday then.

If you are careful enough, you will _________ make mistakes in your exams.