一道英语的选择题:Only after I read the English poem again and again____its real meaning.

问题描述:

一道英语的选择题:Only after I read the English poem again and again____its real meaning.
我选的是would I understand,但答案是did I understand.这是个部分倒装句,可是凭我的感觉用would才对啊?

这个是only 引导的句子,从句用部分倒装的形式,因为是在我一遍又一遍的读过之后才懂得,所以应该用understood ,因为又是部分倒装,所以提助动词到主语之前,所以是did