I. Choose the best answer to complete each of the following sentences.
21. The dogs _____________ fed before they went to the party.
A. has                                      B. have been   C. had been                 D. having been
22. The car was dirty. They    _____________ it for weeks.
A. hasn't cleaned                     B. haven't cleaned      C. hadn't been cleaned            D. hadn't cleared
23. It _____________ her 10 minutes to do this exercise yesterday morning.
A. made                                  B. took                        C. cost             D. lost
24. Frank is capable _____________ doing better than he is doing now.
A. of                                        B. at                            C. with                        D. in
25. The scheme has been set up to help _____________ people.
A. home-made                        B. homeless                 C. house-style D. houseful
26. We're _____________ the evening around a Japanese theme.
A. organizing              B. organizer                 C. organization            D. organized
27. The pollution problems _____________ since last month.
A. has discussed                     B. have discussed      C. has been discussed             D. have been discussed
28. When they got home last night. They found that someone _____________ into the house.
A. had broken             B. had been broken    C. has broken              D. has been broken
29. How many languages are _____________ in Chinese?
A. speak                                  B. speaking                 C. spoken                    D. speaker
30. The woman sitting next to me on the plane was very nervous. She _____________ before.
A. hasn't flown              B. hadn't flown           C. didn't fly                D. doesn't fly