A and B vs. A or B

 

导读：这里较详细地说了两者的逻辑关系，or一般有分离意义，and有结合意义

 

一.  and 与or 的基本逻辑关系

one of A or B 的意思是 "one of A or one of B," 比如, "Take one of the apples or the oranges."  这句话的意思是“从apples中或oranges中拿一个水果”（不是两个或以上，也不是各拿一个以上）

one of A and B的意思与either A or B是相同的。在标准英语中， one of A and B 实际只用于专利申请及某些特殊的专业性语言场合。可以简单使用 A or B.

 1. Take one of the apples or the oranges.  = Take one of the apples or one of the oranges.（总数只拿一个）

 2. Take one of the apple or the orange. = 这句话本身没有什么意义。但如果这里的apple和orange是某种指代（或省略），那又是另外回事了，如：take one of the seeds of the apple or one of the seeds of the orange.除此，人们可能也会理解为对方是想说 "take the apple or take the orange."

 3. Take one of the apples and the oranges. 含糊的语言，它的意思可能是 "take the apples or take the oranges" 还是 "take one (fruit) from the group of apples and oranges combined" (which would more likely be written "take one of the apples and oranges").？

4. Take one of the apple and (the) orange.  [标准英语中该句话不太可能] ，但人们可能会理解为 "Take the apple or take the orange."

5. Take one each of the apples and oranges.  = Take one apple and one orange.

[案例1]

下面这句对吗？

At least one of A and B are toxic.

答：不对。因为主语是one, 除非one代替的是复数名词。

At least one of the apples and oranges is rotten.

At least one of the two teams are going to win.  (This assumes you are treating a team as a plural collective noun.)

[案例2]

There is no school this Thursday or Friday.
There is school on this Thursday and Friday.

有人认为or 来源于nor, 因为在此结构中，or与nor的含义是相同的

There is no school this Thursday nor Friday.
----> There is no school this Thursday or Friday.

[案例3] 高考试题中and, but和or的用法

1. （NMET 2002） Excuse me for breaking in，_____I have some news for you.

　　A. so    B. and      C. but     D. yet

2. （NMET 2003）We're going to the bookstore in John's car. You can come with us ____ you can meet us there later.

　　A. but    B. and      C. or      D. then

答案： 1. C ； 2. C.

but 用于表示歉意的句子中；or 表示选择，在众多情况下选择其一; and, but, or 都属并列连词，其基本用法是用来连接两个相同的语法成分，随意错用，会造成句子结构混乱，语意不清。

【题】

Though he told me a second time about it, _____I didn’t understand.
A. but    B. still    C. however     D. but yet  KeyC
问：B可以吗？是否however后一定要加逗号？

答：在正式的写作中，"however" (作but的含义) 常在分号后起句，也常在其后有逗号，故C并不对。所有这些选项都有些奇怪。这样正常：
He told me about it a second time, but I still didn't understand. ü
He told me about it a second time; however I didn’t understand. ü

Though he told me about it a second time, I still didn’t understand.ü

那些选项都有错误，改正的方式：

A. Though He told me a second time about it, but I didn’t understand.
B. Though he told me a second time about it, still I still didn’t understand.
or B. Though He told me a second time about it; still I didn’t understand.
C. Though He told me a second time about it; however, I didn’t understand.
D. Though He told me a second time about it, but yet I didn’t understand.
or D. Though He told me a second time about it, but yet I didn’t understand. Old fashioned, or perhaps BE.

另外，当however是no matter how的意思时，它后面自然不能用逗号：

I did not understand what he meant, however he might word it.
I did not understand what he meant, however many times he told me.

 

二 . and 的基本用法及考点

　　1. and 表示顺承或递进关系，强调前后的内容与形式一致。例如：

　　Our guide saw me and shouted at me.

 　 One learns a language by making mistakes and correcting them.

　　I'd like to lie down and go to sleep.

　　He told his desk mate to stop writing and to listen to him.

　　2. and 常用在肯定句中列举并列成分，但也可用在否定句中列举并列成分，条件是双重否定句或 and 前后都有否定词。例如：

　　We will be shown around the city： schools， museums，and some other places，where other visitors seldom go.

　　No fly and no mosquito has been found in that modern hotel.

　　Man can't live without air and water.

　　3. and 放句首表示所引出的新内容和句子的关系更紧密。例如：

　　Don't go. They're only dogs. And dogs are our friends now.

　　And as for us，we are fortunate.

三 . but 的基本用法及考点

　　1. but 表示转折关系，强调所引出的内容与前面的内容相对或相反。例如：

　　My name is Robert，but most of my friends call me Bob for short.

　　Someone called me up in the middle of the night，but they hung up before I could answer the phone.

　　2. but 用于表示歉意的“ I'm sorry……， Excuse me…… ”等之后，表示礼貌、拒绝或不同意，这时只起连接作用，无实在意义。例如：

　　I'm sorry，but I don't think I know you.

　  —Do you mind if I smoke here？

　  —I'm sorry，but it's not allowed.

　　注意：若用于对过去事情表示遗憾或请求原谅，不能用 but .例如：

　　I'm sorry that I lost your pen.

　　Excuse me for my being late for class.

　　3. 要避免 although / though……but 用在同一个句子中的错误。但可用副词 yet， still，nevertheless 引出让步意义。例如：

　　Though he is in poor health， but he still sticks to his work. （×）

　　Though he is in poor health， he still sticks to his work.

　　He is in poor health， but he still sticks to his work. （本句连接松散，不算正确）

　　He is in poor health， yet he still sticks to his work…… （？）

　　4. but（except， besides）考点，如其前含“ do ”的不同形式，其后的动词不定式常省去“ to ”；但当这些介词前无“ do ”的某种形式时，其后的动词不定式不能省略“ to ”。例如：

　　Since I was locked in the house，I couldn't do anything but just sit there and wait.

　　We have no choice but to do what we were asked.

四. or 的基本用法及考点

　　1. or 表示选择关系，强调多中选一。例如：

　　Would you like a cup of coffee or shall we get down to business right away？

　　Whether he speaks or not，the result will be the same.

　　2. or 常用在祈使句中，表示前面的条件与后面的结果不一致。 or 可换为 otherwise， or otherwise .例如：

　　We must get up early tomorrow，or we'll miss the first bus to the Great Wall.

　　You must work harder，or you will fail to pass the college entrance examination.

　　3. or 用在否定句中，表示并列成分的列举。例如：

　　I don't like chicken or fish.

　　He didn't care about his kingdom or his people.

　　4. or 用在特殊疑问句表示追加提问，提出几种情况供对方作出肯定答复。例如：

　　——Who is the tallest， Tom， Mary or John？

　　——Maybe Tom.

　　——Which fruit do you like， oranges or apples？

　　——I like apples better.

五 .  A or B的单复数问题

遵循“就近原则”

Reward or punishment is meted out   
Rewards or punishments are meted out
Reward or punishment are meted out

Cash or prizes are awarded.
Prizes or cash is awarded.

 

请做下面的高考选择题：

1. She set out soon after dark ____home an hour later.

A. arriving             B. to arrive          C. having arrived       D. and arrived

2. What the man said sounds unbelievable，___it is true.

A. yet and             B. and yet           C. and but             D. but and

3. The boy had no schooling at all，and he doesn't know how to read ___ how to write.

A. and          B. or               C. but           D. then

4. During the test we were supposed to stay in our seats， keep our eyes on paper，___to anyone.

　　A. and not speak      B. but could not talk      C. or speak         D. rather than speak

5. Generally speaking，it's the greatest happiness on earth____.

　　A. loving and to be loved           B. to love and be loving

　　C. to love and to be loved           D. to love and being loved

6. The Whites should either keep their dogs in the house or____.

A. tie up          B. tying up         C. to tie them up          D. tied up

7. The poor orphan said he had neither father _____mother，_____any brother ____sister.

　　A. nor， or， or       B. or， nor， or     C. or， or， nor       D. nor， or，nor

8. —Coffee___ milk？

　—Only milk， please，___I used to drink coffee.

A. and； but        B. and； and        C. or； and         D. or；but