since的用法:译作“自从…以来” (1)接时间点:如 I have stayed in that country since 1995. 要求:谓v.用现在完成时,而且须是延续性动词. (2)接一段时间 + ago:如 They have lived in that house since two years ago. 要求:谓v.用现在完成时,而且须是延续性动词. (3)接时间状语从句:如 I have loved her since I met her last time. / Lily has stayed at home since she left school. 要求:主句的谓v.用现在完成时,而且须是延续性动词;从句的谓v.用一般过去时,而且须是终止性动词. (4)用于句型“It’s / It has been + 一段时间 + since + 时间状语从句”中,译作“自从…以来, 已经…(时间)了”.如 It’s / has been three months since he moved to this city. 要求:主句的谓v.用一般现在时或现在完成时;从句的谓v.用一般过去时,而且须是终止性动词. (5)用于句型“一段时间 + has passed since + 时间状语从句”中,译作“自从…以来, … (时间)已经过去了”.如上个例句还可写成:Three months has passed since he moved to this city. 要求:主句的谓v.用现在完成时,而且动词必须是has passed;从句的谓v.用一般过去时,而且须是终止性动词. (6)注:当since用于否定句时,主句的谓v.可以是终止性动词.如 He hasn’t seen the film since last month. (7)相关词组:“从那时起”:ever since、since then、from then on. 注:ever since作为一个词组,放句尾可单独使用.如I have given up smoking ever since. 另外,还可在since后接句子.since前加ever,只是加重语气而已.如 I have given up smoking ever since I caught a bad cough. (8) since还可引导原因状语从句,译作“由于;因为”,相当于because.如 Since he was lazy, he didn’t finish his homework.