afterbefore当主句用将来时,他们两个都是从句是用现在时吗?after和before当主句用将来时,他们两个都是从句用现在时吗?其它时候则相反对吗

Question

after before当主句用将来时,他们两个都是从句是用现在时吗?
after 和before当主句用将来时,他们两个都是从句用现在时吗?
其它时候则相反对吗

Answer 1

当after 和before引导时间状语从句时,主句的谓语动词常用一般将来时.
如：He will finish his homework before his father comes back.
It will be a long time before Tom comes back from abroad.
英语中,从句用一般现在时来代替一般将来时的情况还有,在条件状语从句、时间状语从句和让步状语从句中都是属于这种情况.否则,要用将来时.
再如 ：I won't go if it rains tomorrow.