What she did there__ students' eyes.A.open B.open up C.opened up

问题描述:

What she did there__ students' eyes.A.open B.open up C.opened up
答案选opened up 我想请问下为什么用过去式呢
这里是做什么语法来解释啊?

what she did there 她在那做过的事.表示名词.做主语.
她在那做的是让学生们开了眼界.
主语里可以看到did ,表示过去时.谓语动词 open up 要用过去式.