— Where’s Lucy ? —  She ________ in the office. I saw her there just now.

The train is to start soon and Mary hasn’t turned up． What _____ have happened to her?

—Do you know where Mary is? I couldn’t find her anywhere.—Well . She        have gone far—her coat’s still here.

—The research on the new flu virus vaccine is challenging and demanding. Who do you think can do the job?     —_______ my students have a try?

--____________ you sing an English song?--- Yes, I can.