I have been here since I was born 和I haden't seen him since he left NANJING.两句话为什么用的不是相同的时态?

问题描述:

I have been here since I was born 和I haden't seen him since he left NANJING.两句话为什么用的不是相同的时态?

简单的说,两个句子的主句都是可以延续的动作:我一直在这,我再没见过他,都是可以延续的;而我出生和他离开南京是两个瞬时的行为,我总不能是一直在出生,他总不能一直保持离开这个行为.所以两个句子的主句都是完成时,从句都是过去时.