ago用法详解：一般不与遥完成时连用一、规则：在通常情况下 ago 只与过去时连用，而不与遥完成时连用。
因为ago指的是多久以前的过去时间，而遥完成时表示的动作虽然发生在过去，但它强调的是与遥的联系或对遥的影响，因此两者不能用在一起。
如：我两个月前见过他。
误：I have seen him two months ago.
正：I saw him two months ago.
二、特例：但是，有时为了行文的需要或使句子生动，ago可用于类似以下这样的句子：I had thought that he had died at least 20 years ago.
我原以为他至少在< ago.
years 20 least at died had he that>20年前就已经去世了。