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buy是终止性动词，因此在肯定句中不宜与一段时间连用。 例如：

这房子我已买了十年。
正：I bought this house ten years ago.
正：I have had this house for ten years.
正：It’s ten years since I bought this house.
误：I have bought this house for ten years.

所以这道题中，I bought it two years ago. = I have had it since two years ago. = I have had it for two years.

还有这里助助想说，since two years ago这种用法是争议非常大的，很不常见，因为ago不能与完成时连用。所以这里助助不建议同学纠结这里，只要分清楚在延续性动词和终止性动词适用的时态与场合。

1. 延续性动词要点
（1）延续性动词表示能够延续的动词作
如：learn, work, stand, lie, know, walk, keep, have, wait, watch, sing, read, sleep, live, stay等。
（2）延续性动词可以与表示时间段的状语连用。
如：for 2 years / since引导的从句 / since last year / since 5 days ago / how long / for a long time等。

例句:
——He has lived here for 6 years.
——You can keep the book for 5 days.
——I stayed there for 2 weeks last year
——How long did you stay there last year?

2. 非延续性动词要点
（1） 非延续性动词也称终止性动词、瞬间动词, 表示不能延续的动作, 这种动作发生后立即结束。如:
open, die, close, begin, finish, come, go, move, borrow, lend, buy, find等。
（2） 非延续性动词在肯定句中与表示具体时间点的状语连用，如：two years ago; at 5 o'clock
例:
——He died 5 years ago.
（3） 非延续动词不能和表示时间段的状语连用：
例：He has come here for two hours. (错句)

注意：
终止性动词的否定形式可以与表示时间段的时间状语连用。例:
——I haven't left here for 3 years.
——I haven't heard from him for 3 weeks.

希望助助的回答可以帮到你～祝你学习进步～