since two years ago 它是一个时间点 还是一个时间段?

since two years ago 它是一个时间点 还是一个时间段? since 3 years ago是时间点还是时间段 since 3 years ago.是时间点还是时间段 怎么区分英语中的时间点和时间段?例：for 10 years ago ,since ten years ago哪个是时间 have (现在完成式)后面加时间段,那么since one years ago是点时间还是段时间?意思不是在一年之前吗 since+时间段+ago中since是什么词性?介词还是连词? SINCE TWO YEARS AGO的同义句 the swimming club opened two years ago（用since two years ago since two years ago与since two years的区别,分别用在什么时态? Mr green has ()us English since two years ago They ___(live) there since two years ago How long ___ your mother ___?Since two years ago.