It’s the fourth time that heavy smog has hit the city this month. — It’s high time we _______ measures tofight air pollution.

Good teachers can usually give the students______ advice on their study.

Could you do me a favor and take the box up to the sixth floor —- __ ____. No problem at all.

He met a lot of his friends at the party, ______devoted to rural education like him.

The 70-year-old man ______ exercises in themorning.