The children ____ very quiet；I wonder what they ____ up to.

He got well-prepared for the job interview, for hecouldn’t risk ______ the good opportunity.

_____ the city’s public school system should be open to the children of migrant workers has become the focus of discussion.

In my opinion, no search engine can ________ Baidu in search scope and speed. [ ]

“Crash diets” make us lose weight fast and I amall into that —But it_______better to work out