for what seemed to be a very long time如何理解

问题描述

I waited, cold and tired, out of the building for ______ seemed to be a very long time.

A. which      B. that       C. what      D. it

答案是C。请问怎么理解？谢谢！

老师答疑

W老师：

这里的 what 为复合连接代词，在此引导宾语从句（用作介词 for 的宾语），同时 what 在此用作宾语从句的主语。又如：

The young girl was too frightened to speak, standing there for what seemed like hours. 小女孩吓得不敢说话，在那儿站了几个小时。