when _ you_(buy) it?

来源：百度知道 编辑：UC知道 时间：2024/05/22 17:54:32
是否用现在完成时

did buy 因为有个when,强调的是那个时候的动作,所以只用过去时.特点:如果一个动作含有具体的过去时间状语时,该用过去时态,不能用完成时态.
如:--Have you seen my pen? --I saw it just now/2 hours ago/yesterday/last night.

NO必须用一般过去时

when did you buy it?

如果要用现在完成时，必须如下

how long have you bought it?

did buy
buy是瞬间动词，不能用于完成时
这里是你过去的那一个时刻买的？