for通常可以接一段时间，而不能接点时间。
常和现在完成时连用，有时也可以和一般将来时、一般过去时连用。since后面才可以接点时间
I have learned English for one score years.
I haven't seen you for ages.
He has studied Chinese for thirteen years.
He has played the piano for two hours.
温馨提示：
