since 时间 ago 1.since +时间 +ago 2.since 后可以跟个时间,或是直接接句子..那是用在什么时态里面.主句要是什么时态?

since 时间 ago 1.since +时间 +ago 2.since 后可以跟个时间,或是直接接句子..那是用在什么时态里面.主句要是什么时态? for和since的用法since时间后要加ago吗?还是for后加ago? since long ago 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, since加ago还是表示点时间吗 Since 接段时间要用ago吗 since,for,ago与时间搭配的意义曲别 since since +时间点 造句 since +时间点 造句 since+时间段+ago中since是什么词性?介词还是连词? since ten years since ten years ago区别 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? 现在完成时中,for加一段时间是不是等于since加时间点加ago? since 3 years ago是时间点还是时间段为什么呢,麻烦讲清楚 since years ago用于什么时态 SINCE TWO YEARS AGO的同义句 since…ago表示什么时态