Whether and if
Some students may find themselves unsure about when to use “if" and when to use“whether”. Well, you are not alone.
一些学生可能会发现自己不确定什么时候用“if”，什么时候用“whether”。好吧，你其实并不孤单。
Both if and whether are conjunctions, which are words that connect two or more sentences, clauses, or parts of clauses
if和whether都是连词，它们是连接两个或多个句子、从句或从句部分的单词。
There is a reason these words can be tricky: They are sometimes interchangeable, especially when using informal language
这些词的用法很棘手是有原因的:它们有时是可以互换的，尤其是在使用非正式语言时: For example:例如
.Jamie called the restaurant to see if it was open.
·杰米打电话给餐馆看它是否开门。
.Jamie called the restaurant to see whether it was open.
·杰米打电话给餐馆看它是否开门。
These sentences mean the same thing.
However, using the word if in this manner is considered informal language.
这些句子的意思是一样的。然而，以这种方式使用if这个词被认为是非正式语言。
The conjunction if must be used in a conditional sentence.
连词if必须用在条件句中。
A conditional sentence is one in which the outcome depends on a certain circumstance, or where a situation is hypothetical. In other words, when A happens, B happens.
条件句是指结果取决于特定的情况，或者假设的情况。换句话说，当A发生时，B发生。 For example:例如
·We can play outside if the sun comes out.
如果太阳出来了，我们可以在外面玩。
·Beggars would ride if wishes were horses.
假如愿望都能实现，乞丐都会发财。
In these two examples, “if the sun comes out” and “if wishes were horses”are conditions and “we can play outside" and “beggars would ride” are the result.
在这两个例子中，“如果太阳出来了”和“如果愿望都能实现”是条件，“我们可以在外面玩”和“乞丐会发财”是结果。
The conjunction whether must be used when there are two alternatives or a choice.
当有两个选项或一个选项时，必须使用连词whether.
·I don't know whether he prefers daffodils or marigolds
·我不知道他喜欢水仙花还是金盏花。
.It doesn't matter whether you read the book tonight or tomorrow night.
·你今晚读这本书还是明天晚上读这本书都没有关系。
Additionally, whether must always be used when it precedes an infinitive with the word to.
此外，whether必须在不定式前加to时使用。
·I am unsure whether to accept a ride from that gentleman.
·我不确定是否要让那位先生载我一程。
.Have you decided whether to go to college?
·你决定要不要上大学了吗?
The conjunction whether is also used after a preposition.
连词whether也用在介词后面。
Jamie was concerned about whether to close the window.
·杰米担心是否要关上窗户。
·The answer depends on whether you ask the right question
·答案取决于你是否问对了问题。
Remember, if is used when the sentence is conditional. Whether is used when the sentence is discussing a choice or two
alternatives, and is used before an infinitive using the word to and after a preposition.
记住，if用于条件句。Whether在句子讨论一个或两个选择时使用，用在不定式to之前，介词之后。
以上内容来源六分钟英语
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