21. _         the early flight, we ordered a taxi in advance and got up very early.

  A. Catching               B. Caught           C. To catch         D. Catch

22. I was just talking to Margaret when Jackson ____.

 A. cut in             B. cut down          C. cut out         D. cut up

23. The engine just won’t start. Something seems ______ wrong with it.

  A. to go          B. to have gone          C. going           D. having gone

24.Tom, as well as his friends who________ football, _________very popular among the students.

A. likes; are           B. likes; is         C. like; is         D. like; are