Onlyafterhehadspentseveralnightsworkingonthemathsproble...

问题详情：

Only after he had spent several nights working on the maths problem ________to  wonder whether the problem was wrongly set.

A．he began  B．that he began

C．he did begin  D．did he begin

【回答】

D　考查倒装句。当“only＋状语”放在句首时，主句要用部分倒装结构。

知识点：倒装与省略

题型：选择题