曾经在贴吧我回答过的,复制过来参考一下: since when 有2个用法与意思 1,单纯的疑问句中,翻译为“从什么时间开始。。”表示惊讶或者愤怒。 Since when has he been missing?他是从什么时间失踪的?《牛津高阶英汉双节词典》第4版(商务印书馆,牛津大学出版社)第1730页。 Since when =Since what time: Since when has it been any of your business what I do?.我什么时间开始做不关你的事吧?《朗文当代英语词典》第三版增补本(英文版,我自己翻译的,也许不确切)(外语教学与研究出版社)第1630页。 since when ...?spoken used to show that you are very surprised or angry: Since when have you been interested in my feelings?。你什么时候对我的情感感兴趣了?《朗文当代英语词典》最新英文版,网络版,(该书市场上有最新版定价129,我现在家里没有,无法说出具体在那页) since when 的第二个用法可以看做是since +when 的定语从句,相似的用法还有before when.by when. since when 翻译为“在那以后”,至于这里的when是关系副词还是关系代词,国内的专家意见不统一,两种说法都有人支持。与单独的when引到的定语从句比,后者只表示“那时候”。 I came here in 1950,since when I have been engaged in this work 1950年我来到这儿,那以后我一直从事这份工作。 Two years ago I bought a packet of your razor blades,since when I have used no others.(英语语法大全)。两年前我买了你们的一包剃须刀片,从那以后我没有用过别的。 She joined the editorial staff of a local newspaper,since when she has contributed to various monthlies.(同上)她加入了一家地方报纸的编辑组,从那时开始她为各种各样的月刊投稿。 they left on monday,since when we have heard nothing.(张道真现代英语用法词典),楼主自己翻译 类似的before when.by when. I went to bed at ten,before when I was reading for an hour.(张道真) next summer,by when the house should be ready.(张道真) next may,by when the new house should befinished(朗文当代)