介词before 与 after 的⽤法
before”与“after”？
2008-01-16 18:16:28
⽤汉语表达时间的先后时，⼈们通常⽤“以前”和“以后”，词的变化不⼤，⽽且重复率⾮常⾼。受此影响，不少学⽣在英语⾥也千篇⼀律地⽤“before”和“after”来表达这两层意思。其实在英语词汇⾥可以表达这两层意思的词有很多个，其中有⼏个使⽤频率特别⾼，但它们在⽤法上有差异，极易混⽤。掌握这些词的⽤法，正确区分它们的差异，可以帮助我们写作时避免⽤词重复，结构单调，使⽂章⽣动。由于这些词属于⾼频词，把握好这些词，对准确理解和翻译也不⽆帮助。下⾯就对相关词进⾏归纳和⽐较。
⼀、表达“在……之前”的词
1. before prep. , adv. conj.
(a)To my knowledge it has never been done before.
据我所知，以前从未有⼈这样做过。
(b)My father died before I was born.
我⽗亲在我出⽣之前就去世了。
(c)Before being supplied to hous, the water must be treated to make it suitable for drinking.
⽔在供给各⽤户之前应加以处理使之适于饮⽤。
2. until prep. , conj.
(a)Until the twentieth century man ud water, wood and fossil fuels as sources of power.
在20世纪以前，⼈们使⽤⽔、⽊柴和矿物燃料来作能源。
(b)Until penicillin was developed, man could do little with the dia.
在研制出青霉素之前，⼈类对这种病毒⼏乎⽆能为⼒。
(c)Color was a mystery until the time of Newton.
在⽜顿时代以前，颜⾊是个神秘的东西。
［注］：before与until当连词⽤时，都表⽰主句的情景发⽣在从句情景之前，它们主要有两个区别：
第⼀，带有until从句的肯定式主句中的谓语动词必须是持续性的（如be, live, like, work等），⽽带before从句的主句中的谓语动词则不必是持续性的。⽐较：
(a)We always have to wait until the last pasnger has left.
我们总是得等到最后⼀个乘客离去。
(b)I shouted before the boss arrived.
在⽼板到来之前，我⼤喊⼤叫。
第⼆，until引出的分句的内容是真实的，⽽before引出的分句的内容可能是真实的，也可能是⾮真实的。⽐较：
(a)Let's wait until the rain stops.
让我们等到⾬停吧。
(b)I began to cry before he could speak.
他尚未开⼝，我就开始哭了。
(c)Pigs will fly before he'll become a mathematician.
他要是能当数学家，猪都会飞了（在他成为数学家之前猪都会飞了。意即根本不可能）。
3. Previous a. ,adv.
(a)With the help of his coach, he has recovered to the previous level.
在教练的帮助下，他已经恢复到以前的⽔平。
［注］：previous当副词⽤常与to连⽤
(b)You are expected to make full investigations previous to reaching a conclusion.
希望你们下结论之前先作先分调查。
(c)Previously, the local people ud wood and coal to provide power and heating.
以前，当地⼈⽤⽊柴和煤来提供动⼒和燃料。
4. prior (to) a. ,adv.
(a)It happened prior to the warning of the government.
这发⽣在政府发出警告以前。
(b)The contract will be signed prior to the ceremony.
合同将在仪式之前签署。
(c)It is believed that the skill was developed prior to Ming Dynasty.
⼈们相信这项技术在明朝以前就已经发明了。
［注］：prior to和before虽然可以通⽤，但有⼈认为prior to避免⽤在句⾸。
⼆、表达“在……之后”的词
1. after prep. , adv. conj.
(a)After testing, the engine was put into immediate rvice.
经过试验以后，发动机⽴即交付使⽤。
(b)It happened twenty years after.
这事发⽣在20年之后。
(c)After one cycle is completed, another cycle begins.
⼀个循环完成后，另⼀个循环⼜开始。
2.in prep.
(a)In about five years, what I have said today will become true.
⼤约5年以后，我今天所说的就会变成现实。
(b)In the four years that followed, I studied in the Department of Accounting.
在以后的4年中，我在会计系学习。
(C)It's two o’ clock. I'll come in an hour.
现在是两点，我⼀⼩时后到。
［注］：在表⽰以现在为起点的“在……之后”这个含义时，介词in之后应接时间段(a period of time)，介词after之后则应该接时间点(a point of time)。⽐较：
(a)I've ordered a taxi. It will arrive here in 10 minutes.
我已经叫了出租车，10分钟以后就会到。
(b)He will graduate in four years.
他4年以后毕业。
(c)He will be back after three o'clock.
他3点以后到。
但是，当以某个过去的时间为起点时，after之后既可以接时间点，也可以接时间段。⽐如：(a)Just after six the meeting was over.
刚过6点，会议就结束了。
(b)After half month of war Japan was badly defeated.
经过半个⽉的战争，⽇本被打得惨败。
(c)After ven days of this I went to a party.
这样过了7天以后，我去参加⼀个聚会。
3. later
(a)Fuller report will be published at a later date.
更详细的报告会在以后出版。
(b)I don't know what would happen later on.
⾄于以后怎么样，我就不知道了。
(c)He handed in his resignation, and later (on)regretted his hasty action.
他交了辞职书以后，⼜为⾃⼰的草率感到后悔。
［注］：later还可译为“过⼀会⼉”，“过了⼀会⼉”，“后来”等。
4.afterward(s) adv.
(a)She had her supper and went bed soon afterwards.
她吃过晚饭之后不久就去睡觉了。
(b)I didn't e him afterwards.
以后我再也没有见到他了。
(c)I was a bit rude to her at the meeting, and afterwards I apologized.
在会上我对她是有点粗暴，但是（散会）以后我向她道了歉。
