四个月前英语

four（四） （英语无量词）months（月，可数名词复数th结尾加s） ago（...之前） 本句用在句首用逗号与主句隔开，用在句尾则不用。

i bought it in 4 months ago it is my mother gave me a birthday present

I bought it four months ago,it's my mom's birthday gift

I had bought it four monthes ago,it' my birthday gift from my mom.