内容简介

引导词 “if” 既可以表示 “如果”，也可以表示 “是否”。在表示 “是否” 的意思时，有时 “if” 和 “whether” 可以互换使用。这就难倒了一些英语学习者 —— 什么时候该用 “if”？什么时候该用 “whether”？主持人 Sam 总结了两个规则，帮助你判断到底是用 “if” 还是 “whether”，看视频。

文字稿

When do we use if and when do we use whether? Let's take a look.

The simple rule is that with conditional sentences we use if, and when we have two options, we use whether.

If I get hungry, I'll have a snack.
But I don't know whether to have an apple or a biscuit.

When asking an indirect yes/no question, we can use either if or whether – both are correct.

Do you know if the apples are fresh?
Do you know whether the biscuits are any good?

Whether is maybe a little bit more formal, but with both questions there are only two possible answers – yes or no.

用法总结

1. 条件句中，用 “if” 表示 “如果”, 不能用 “whether”。

• If I get hungry, I'll have a snack.
• I'll take an umbrella if it rains.

2. 陈述句中提及两种选择时，常用 “whether”。

• I don't know whether to have an apple or a biscuit.
• I can't decide whether to go home or not.

3. 间接一般疑问句中，“if” 和 “whether” 都适用，同样表示 “是否” 的意思。“Whether” 更正式一点。

• Do you know if the apples are fresh?
• Do you know whether the biscuits are any good?
• Can you tell if it's going to rain today?
• Can you tell whether it's going to rain today?