vt. & vi.转变 change or exchange

　～ away　拿回来
　～ off　关，截断
　～ off the radio　关掉收音机
　～ on　开，接通，使入迷
　～ on the light　开灯
　～ over　换位置，转换
　～ round　转过来
　～ through　转接
　～ back to　回复到
　～ off to another line of thought　改变想法〔思路〕
　～ out of　从…抢走
　～ over to offensive　转入进攻
　～ from　从…转变
　～ from English into Russian　由英语改为俄语
　～ into　变为
　～ to　转向
　～ to the metric system　转换成公制
　～ one's support to the other candidate　转向支持另一候选人

　The train was switching.　火车正在换道。
　He used to smoke this brand of cigarettes, but he switched.　他本来抽这种牌子的香烟，但他后来改抽别的牌子了。
　Don't switch the light.　不要开灯。
　They are switching the tram.　他们使电车换了轨道。
　When will the high-up switch Tony and Denis?　上级什么时候调动托尼和丹尼斯的工作?
　They kept switching meeting places.　他们不断改变碰头地点。
　They switched positions.　他们交换过位置。
　He is always switching jobs.　他总是变换工作。
　They switched sides.　他们改变了立场。
　They switched the conversation when she came in.　她进来时他们就改变了谈话内容。
　His mind switched direction.　他的思路变了。
　His father switched him when he was disobedient.　他不听话时，父亲就鞭打他。
　He switched his horse to make it go faster.　他用鞭打马，让马跑得更快些。

 ♣ switch back　(v.+adv.)
　改而恢复原办法　change one's plans so as to return (to someone or sth else)
　The system doesn't work too well, so we may have to switch back.　这套办法不怎么好，所以我们可能还得恢复原来的办法。
 ♣ switch from　(v.+prep.)
　使…转变〔转移〕　(cause to) move or change from (someone or sth) (to someone or sth else)
　In Japan, Lu Hsun switched from medicine to literature.　在日本，鲁迅弃医从文。
 ♣ switch off　(v.+adv.)
1. 关闭 turn off by means of a switch
　Don't forget to switch off the lights when you leave the classroom.　离开教室时别忘了关灯。
　He switched off the light as there was no one in the room.　他把灯关了，因为房里没有人。
　When the clock struck twelve, I switched off TV and went to bed.　时钟敲响十二点时，我关了电视上床睡觉。
　Adden switched off the radio and started to concentrate on his homework.　阿顿关掉收音机聚精会神地做功课。
　Make sure the current is switched off at the mains before you leave on holiday.　你出去度假前一定要把总电源切断。
2. （使）没兴趣 (cause to) make sb dull, lifeless, unresponsive
　The students started to switch off after the first speech.　学生们听完第一个人发言后就开始心不在焉了。
　The lecture was so boring that I switched off very soon.　讲座非常枯燥，刚坐了一会儿我就开小差了。
　The boy often switches off in class so that he never gets good mark in exam.　那个男孩上课经常走神，所以从来没得过好成绩。
　The party was so dull that it switched him off.　聚会单调乏味，使他感到很扫兴。
　Parties switched me on, but they seemed to switch her off.　聚会使我兴奋，但似乎使她扫兴。
3. 使…停止谈话 stop (someone) talking
　Switch that fellow off!　别让那个家伙再讲下去！
 ♣ switch on　(v.+adv.)
1. 打开，开动，启动 cause (someone) to start working; start working
　She switched on the light.　她打开了电灯。
　Switch on the TV.　打开电视。
　Let's switch on the tape-recorder and enjoy music for a while.　让我们打开录音机，欣赏一会儿音乐吧。
　First you should switch the machine on.　你得先把机器打开。
2. （使）感兴趣，兴奋 (cause to) become interested or excited
　These parties switch him on, but they seemed to switch her off.　这些社交聚会使他兴致勃勃，但似乎使她扫兴。
　That music really switches me on.　那音乐的确使我入迷。
 ♣ switch out　(v.+adv.)
　关上　cause (an electric light) to stop burning
　Please switch out all lights as you leave the building.　离开这所房子时，请把所有的灯都关上。
 ♣ switch over　(v.+adv.)
1. 转换电流 change the current in (an electrical machine)
　You can switch over from one circuit to another without any difficulty.　你可以毫无困难地从一个电路转换到另一个电路。
　The power machine will be switched over at midnight.　发电机午夜转换电流。
2. （使）交换位置 (cause to) exchange places
　We switch over?I'd like to sit in the sun, too.　咱们换换位置好吗?我也想晒晒太阳。
　If you switch the words over, the sentence sounds better.　如果你把这几个词调换一下位置，这句子听起来就好多了。
3. （使）变换，转换 (cause to) make a complete change (to sth else)
　In 1971 Britain switched over to decimal money.　英国在1971年把钱币改成了十进位。
　Many factories are switching over to a shorter working week.　很多工厂都在减少每周的工作日数。
　We are switching over to a new technique next year.　我们将在明年改用一种新技术。
　The chairman decided to switch the factory over to bicycle production.　董事长决定该厂改产自行车。
 ♣ switch round　(v.+adv.)
　调换位置　(cause to) exchange place
　Can we switch round?I'd like to sit in the sun, too.　咱们换换位置好吗?我想晒晒太阳。
　If you switch the words round, the sentence sounds better.　你把这几个词换换位置，这句子听起来就好多了。
 ♣ switch to　(v.+prep.)
　转换　(cause to) move or change (from someone or sth) to (someone or sth else)
　He got tired of teaching and switched to writing stories.　他厌倦了教书，于是改行写小说。
　We used to have coal fires, but now we have switched to gas.　我们过去烧煤取暖，但现在已改用煤气。
　I don't like this TV programme, let's switch to another one.　我不喜欢这个电视节目，换个频道看看吧。
　I would like now to switch to quite a different subject.　现在我想换一个完全不同的话题。
　Don't hang up, please. I'll switch you to my boss.　请别挂断电话。我这就给你接到我的上司那边去。
　He switched the control-lever to "off" position.　他把控制杆拨到“关”的位置。
　Let's switch the discussion to another topic.　咱们换个话题讨论吧。
　They switched the discussion to an argument.　他们把讨论变成了争论。
　It is time to switch the talks to a different subject.　该讨论另一个主题了。
　They switched the conversation to a less embarrassing subject.　他们把谈话转向了不太尴尬的话题。
　She switched her support to the other candidate.　她转而支持另一个候选人。

　switch　也可用作名词，意思是“开关”“改变，转变”。例如：
　Where is the light switch?　电灯开关在哪儿?
　We had to make a switch in our arrangements.　我们不得不对我们的安排做些变动。

　［同义词］ change, exchange, move
　［词源］中古荷兰语swijch（枝）