The students looked after the disabled all the year round as if they were their sons and daughters

问题描述:

The students looked after the disabled all the year round as if they were their sons and daughters
这句话主句为什么不用过去将来时?像这样的句子,主句和从句应该用 什么时态有什么规律吗?

这句话的主句可以用将来时,但表达的意思跟原句不同了.用将来时,表示他们准备做但还没做.
无论主句用的是将来或过去时,从句部分不变.因为英文中的as if通常跟虚拟语气.
当主句用将来时,从句用一般过去时,没错.
当主句用过去时,从句用一般过去时,也没错 (只是在陈述一个“事实”,没有时间范围).