since 3 years ago是时间点还是时间段为什么呢,麻烦讲清楚

I have arrived here since 3 years ago.arrive是瞬间动词,since 3 years ago是表示瞬时还是延续的时间? since 3 years ago是时间点还是时间段为什么呢,麻烦讲清楚 怎么区分英语中的时间点和时间段?例：for 10 years ago ,since ten years ago哪个是时间点哪个是时间段为什么 since 3 years ago.是时间点还是时间段3 years ago.是时间点还是时间段.2.since 1985 是时间点 还是时间段?3.It is +一段时间+ since从句.怎么翻译?自从.已经多少年了》?是这样翻译吗我在网上查的说，sinc many years ago表示的是时间点吗?那就不对了，since 后只能加时间点，since many years ago 的说法就解释不通了。这样说差不多了。请你去有道例句里看有没有since many years ago！ 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 ten years since ten years ago区别 since years ago用于什么时态 SINCE TWO YEARS AGO的同义句 since three years ago 句子要用在 现在完成里吗?We __B__ english since three years ago.A.learned B.have learned Tom has been in Paris since 2 years agoI have been here since five months ago.问：1.since+时间+ago 在句子里怎么翻译, I have known sandy since three years ago以 since three years ago ,提问 she's been swimming since she wassix years ago划线提问since she wassix years ago Lin Tao has been a teacher ()答案是since two years ago 为什么不能是since he comes here How long have you been playing the piano?_______是填Since five years ago还是for five years 简单的英语句子,看看有错吗we have be classmate since 3 years ago since 和agosince 后面不能 和ago 连用（朗文字典里说的）那我要表示 since two years ago 这个概念的时候, ago 换成什么词? （ 以现在的为时间点,算起） 在现在完成时态 since 引导的句子中,主句的谓语动词必须用持续动词吗?He has left here since two years ago.He has been away since two years ago.是两个都对,还是有错? The Browns are living a hard life because MR.BROWN______A was jobless since three years ago B has been out of work for 3 years ago C has lost his job for 3 years D was fired three years ago