Our teachers often ask us over the answers carefully before handing in our papers.A. goB.

问题补充：

Our teachers often ask us over the answers carefully before handing in our papers.

A. go

B. going

C. to go

D. gone

答案：

A. go

B. going

(答案→)C. to go

D. gone

解析：考察动词固定搭配。固定搭配ask sb to do sth要求某人做某事；句意：我们的老师经常要求我们在交卷之前认真检查答案。句中的不定式to go over the answers在句中作宾语补足语。故C正确。