since/ for (1) since用于完成時態(tài).既能用作介詞.也能用作連詞.后常接時間點.意思是“自從 . He has been a worker since he came into this city. 自從他來到這個城市.他就是工人了. I have never seen him since we last met in Shanghai . 自從我們上次在上海見過之后.我再也沒見過他. since作連詞.還有“既然 的意思. Since you are interested in it, just do it. 既然你對它感興趣.那就做吧. You can have fun now since you’ve finished your work. 既然你已經(jīng)做完了功課.就開心玩會兒吧. (2) for用于完成時.用作介詞.后常接一段時間.意思是“經(jīng)過- . I have learned English for five years.我已經(jīng)學了五年英語了. They have waited for you for 30 minutes.他們已經(jīng)等了你三十分鐘了. for也可以用作連詞.但意思是“因為 . They missed the flight for they were late.他們由于完到了而誤了航班. He fell ill for many reasons.他由于多種原因病倒了. 【查看更多】
