当when引导时间状语从句的时态问题
1个回答

when引导的时间状语可以是现在时,主句用一般将来时(情态动词,祈使句),如:

When he comes,I will tell you.

when引导的时间状语用过去时,主句用过去进行时,如:

I was having breakfast when he arrived.

when引导的时间状语用过去时,主句用过去完成时,如:

When we got to the station,the train had already left.

when引导的时间状语用过去进行时,主句用过去时,如:

He arrived when I was taking breakfast.