for +時間：可用一般現在時，一般過去時，一般將來時，過去將來時，現在完成時，現在完成進行時，過去完成時，過去完成進行時。如：He works for six hours every day. He stayed there for two days.He will stay there for two days. He said he would stay there for two days.He has stayed here for two days. He has been staying here for two days.He said he had stayed here for two days. He said he had been staying here for two days.since +時間：since從句用一般過去時，主句用現在完成時或者現在完成進行時。如：He has been working hard since he came here.Great changes have taken place in China since you left here.He has known her since two years ago.
for +時間：可用一般現在時，一般過去時，一般將來時，過去將來時，現在完成時，現在完成進行時，過去完成時，過去完成進行時。如：He works for six hours every day. He stayed there for two days.He will stay there for two days. He said he would stay there for two days.He has stayed here for two days. He has been staying here for two days.He said he had stayed here for two days. He said he had been staying here for two days.since +時間：since從句用一般過去時，主句用現在完成時或者現在完成進行時。如：He has been working hard since he came here.Great changes have taken place in China since you left here.He has known her since two years ago.