问题补充:
(·成都一模) all the homework assigned by the school, the students have to work at it till midnight.
A. Completing
B. To complete
C. Having completed
D. To have completed
答案:
A. Completing
(答案→)B. To complete
C. Having completed
D. To have completed
解析:选B考查非谓语动词。此处为目的状语, 因此使用不定式,排除A和C,而且不强调完成,因此使用不定式的一般式,故选B。