They really don’t know how _________ the difficult problem.
Because Robert was seen ____ the room, everyone thought he was the thief. A. to enter B. enter C. Entered
______ has Miss Green taught in your school? For about six years.A. How long B. How soon C. How far
I hear there will be all kinds of robots________ twenty _____ time .A. after, years B. in, years’ C. for, year’s
I know Beijing very well since I ________ there three times.A. have been B. went C. have gone
-- You look very worried. _______? -- My new car hurt an old woman.A. Can I ask a favour B. How do you do C. What’s up