This city plans to ________ all high-polluting factories by the end of 2018 so as to improve its air quality.

To keep you______, you’d better ______ helmet(头盔) when you skate on real ice.

My aunt has been a teacher threeyears ago.

You must cut up ______ onion and ____ tomato first.

uhao has followed a markedlydifferent path to ____ of the giant Yao Ming, who was the overall first draftpick in 2002