I couldn't see anything unusual in this room.请问这里的see为什么不用过去时?

问题描述:

I couldn't see anything unusual in this room.请问这里的see为什么不用过去时?

因为前面有情态动词could ,情态动词后接动词原形.故SEE 不用过去时.
加油!不明白再问!