There _____ lots of bad information which is not ____ for teenagers on the Internet.

The old tower must be saved, _______ thecost.

—Do you think we should accept that offer?—Yes, we should, for we ________ such bad luck up till now, and time ________ out.[ ]

The number of smokers in China ________increased in recent years, and a number of them _________ the youth.

____________ careful you are, _____________ mistakes you’ll make.