since的用法：譯作“自從…以來”
(1)接時(shí)間點(diǎn)：如 I have stayed in that country since 1995.要求：謂v.用現(xiàn)在完成時(shí),而且須是延續(xù)性動(dòng)詞.
(2)接一段時(shí)間 + ago：如 They have lived in that house since two years ago.要求：謂v.用現(xiàn)在完成時(shí),而且須是延續(xù)性動(dòng)詞.
(3)接時(shí)間狀語從句：如 I have loved her since I met her last time./ Lily has stayed at home since she left school.要求：主句的謂v.用現(xiàn)在完成時(shí),而且須是延續(xù)性動(dòng)詞；從句的謂v.用一般過去時(shí),而且須是終止性動(dòng)詞.
(4)用于句型“It’s / It has been + 一段時(shí)間 + since + 時(shí)間狀語從句”中,譯作“自從…以來,已經(jīng)…(時(shí)間)了”.如 It’s / has been three months since he moved to this city.要求：主句的謂v.用一般現(xiàn)在時(shí)或現(xiàn)在完成時(shí)；從句的謂v.用一般過去時(shí),而且須是終止性動(dòng)詞.
(5)用于句型“一段時(shí)間 + has passed since + 時(shí)間狀語從句”中,譯作“自從…以來,…
(時(shí)間)已經(jīng)過去了”.如上個(gè)例句還可寫成：Three months has passed since he moved to this city.要求：主句的謂v.用現(xiàn)在完成時(shí),而且動(dòng)詞必須是has passed；從句的謂v.用一般過去時(shí),而且須是終止性動(dòng)詞.
(6)注：當(dāng)since用于否定句時(shí),主句的謂v.可以是終止性動(dòng)詞.如 He hasn’t seen the film since last month.
(7)相關(guān)詞組：“從那時(shí)起”：ever since、since then、from then on.
注：ever since作為一個(gè)詞組,放句尾可單獨(dú)使用.如I have given up smoking ever since.另外,還可在since后接句子.since前加ever,只是加重語氣而已.如 I have given up smoking ever since I caught a bad cough.
(8) since還可引導(dǎo)原因狀語從句,譯作“由于；因?yàn)椤?相當(dāng)于because.如 Since he was lazy,he didn’t finish his homework.