问题:
Tom often helps his classmates ________ their bikes after school.
A.fix up
B.cheer up
C.put up
D.call up
Tom often helps his classmates ________ their bikes after school.
A.fix up
B.cheer up
C.put up
D.call up
A.fix up
B.cheer up
C.put up
D.call up
参考答案: