英语语法：64 If Versus Whether

Grammar Girl here. Today's topic is whether--not rain or sunshine, but whether w-h-e-t-h-e-r, as in whether you like it or not, it's the topic.

[Listener question about if versus¹ whether and whether you need an or not after whether]

Well, it's been a while since the listener called in those questions, so I hope people are speaking to each other by now. But they are great questions.

First, let's figure out when to use whether and when to use if.

If Versus Whether

Although in informal writing and speech the two words are often used interchangeably, in formal writing, such as in technical writing at work, it's a good idea to make a distinction between them because the meaning can sometimes be different depending on which word you use. The formal rule is to use if when you have a conditional² sentence and whether when you are showing that two alternatives are possible. Some examples will make this more clear.

Here's an example where the two words could be interchangeable:

Squiggly didn't know whether Aardvark would arrive on Friday.

Squiggly didn't know if Aardvark would arrive on Friday.

In either sentence, the meaning is that Aardvark may or may not arrive on Friday.

Now, here are some examples where the words are not interchangeable.

Squiggly didn't know whether Aardvark would arrive on Friday or Saturday.

Because I used whether, you know that there are two possibilities: Aardvark will arrive on Friday or Aardvark will arrive on Saturday.

Now see how the sentence has a different meaning when I use if instead of whether:

Squiggly didn't know if Aardvark would arrive on Friday or Saturday.

Now in addition to arriving on Friday or Saturday, there is the possibility that Aardvark may not arrive at all. These last two sentences show why it is best to use whether when you have two possibilities, and that is why I recommend using whether instead of if when you have two possibilities, even when the meaning wouldn't change if you use if. It's safer and more consistent³.

Here's a final pair of examples:

Call Squiggly if you are going to arrive on Friday.

Call Squiggly whether or not you are going to arrive on Friday.

The first sentence is conditional. Call Squiggly if you are going to arrive on Friday means Aardvark is only expected to call if he is coming.

The second sentence is not conditional. Call Squiggly whether or not you are going to arrive on Friday means Aardvark is expected to call either way.

So to sum up, use whether when you have two discrete⁴ choices or mean "regardless of whether," and use if for conditional sentences.

Whether Versus Whether or Not

That last example is also a good lead in to the second part of the caller's question: when do you need an or not after whether? Why did I say, "Call Squiggly whether or not you are going to arrive on Friday"?

Often, the or not is just extra fluff and should be left off. In my first example, where I said, "Squiggly didn't know whether Aardvark would arrive on Friday," adding an or not wouldn't change the meaning or emphasis⁵. Squiggly didn't know whether or not Aardvark would arrive on Friday means the same thing as Squiggly didn't know whether Aardvark would arrive on Friday. Or not is superfluous⁶, so leave it out.

On the other hand, you need the full phrase whether or not when you mean "regardless of whether." It shows that there is equal emphasis on both options.

Call Squiggly regardless of whether you are going to arrive on Friday.

Call Squiggly whether or not you are going to arrive on Friday.

Finally, a listener wrote to say that her boss was driving her crazy by saying "rather or not" instead of "whether or not." So I'll add that "rather or not" is incorrect; whether is a conjunction⁷ and rather is an adverb, and they are not interchangeable. "Whether or not" is the correct way to show that there are two possibilities or you mean "regardless of whether."

Questions and comments for me go to...or the voicemail line at 206-338-GIRL. You can also read the full transcript⁸ of this podcast at quickanddirtytips.com, where you can leave comments and check out the other great podcasts. We've launched⁹ a new show I expect you'll all like called the Make-It-Green Girl, so check it out.
 

1 versus   

prep.以…为对手，对；与…相比之下

参考例句：

• The big match tonight is England versus Spain.今晚的大赛是英格兰对西班牙。
• The most exciting game was Harvard versus Yale.最富紧张刺激的球赛是哈佛队对耶鲁队。

2 conditional   

adj.条件的，带有条件的

参考例句：

• My agreement is conditional on your help.你肯帮助我才同意。
• There are two forms of most-favored-nation treatment:conditional and unconditional.最惠国待遇有两种形式:有条件的和无条件的。

3 consistent   

adj.坚持的，一贯的，一致的，符合的

参考例句：

• He has been a consistent friend to the Chinese people.他是中国人民始终如一的朋友。
• His action is always consistent with his words.他始终言行一致。

4 discrete   

adj.个别的，分离的，不连续的

参考例句：

• The picture consists of a lot of discrete spots of colour.这幅画由许多不相连的色点组成。
• Most staple fibers are discrete,individual entities.大多数短纤维是不联系的单独实体。

5 emphasis   

n.强调，重点，重要性

参考例句：

• The emphasis has shifted markedly in recent years.最近几年重点已经明显改变了。
• Particular emphasis will be placed on oral language training.将会特别强调口语训练。

6 superfluous   

adj.过多的，过剩的，多余的

参考例句：

• She fined away superfluous matter in the design. 她删去了这图案中多余的东西。
• That request seemed superfluous when I wrote it.我这样写的时候觉得这个请求似乎是多此一举。

7 conjunction   

n.联合，连接，接合；连接词

参考例句：

• Two or more sentences may be joined together by a conjunction.两个或两个以上的句子可以用连词连接。
• The conjunction of heavy rains and high winds caused flooding.暴风雨的同时发生引起了洪水泛滥。

8 transcript   

n.抄本，誊本，副本，肄业证书

参考例句：

• A transcript of the tapes was presented as evidence in court.一份录音带的文字本作为证据被呈交法庭。
• They wouldn't let me have a transcript of the interview.他们拒绝给我一份采访的文字整理稿。

9 launched   

v.发射( launch的过去式和过去分词 )；[计算机]开始（应用程序）；发动；开展（活动、计划等）

参考例句：

• He launched a bitter diatribe against the younger generation. 他对年轻一代发起了猛烈的抨击。
• The product was launched amid much fanfare worldwide. 这个产品在世界各地隆重推出。