题目内容：

for和since一样,也要用延续性动词吗,for和since一样,主句是现在完成时,从句是一般过去时吗?
为什么这一句,I have lived in xu zhou since I left nanjing,为什么不用For,要用since呢,用for可以吗

优质解答

1.for和since引导短语/从句在句中做时间状语时,如果该句是肯定句,则要求句子谓语动词是延续性动词.但是如果句子为否定句,则无此要求.如：I have lived here for 3 years.= I have lived here since 3 years ago.I ha...