How to Use Must in English - English Modal Verbs

英语语法- 情态动词 MUST

Hi, I’m Oli.

嗨，我是Oli。

Welcome to Oxford Online English!

欢迎来到Oxford Online English！

In this lesson, you can learn about the verb 'must'.

在本节课里，您可以学到动词 “must”。

'Must' can have many different meanings in English.

“Must”在英文里可以有 很多不同的意思。

In this video, you can learn about the different meanings of 'must', and how to use 'must'

在本视频里，您可以学动词“must”的不同 意思，以及怎样在

in English.

英文里用“must”。

Part one, using 'must' to talk about obligations.

第一部分，使用“must”来谈论责任。

First, you can use must to talk about obligations and rules.

首先，您可以用“must”来谈论 责任和规则。

For example:

例如：

"I must remember to call her—it’s her birthday."

"I must remember to call her—it’s her birthday."

This is an obligation.

这是一个责任。

It’s very important to me.

那对我很重要。

"All passengers must hold a valid ticket."

"All passengers must hold a valid ticket."

This is a rule.

这是一个规则。

You can't choose to travel without a ticket.

您不能没有机票就要去旅行。

These are things that it is necessary or important to do.

有些事是有必要做或重要的。

If you must do something, you have no choice.

如果您必须要做某些事，您没有选择。

When you use must for obligations, it can mean that the obligation is important to you

当您使用"must"来谈责任时，它可以 意味着责任对您个人

personally.

而言很重要。

It’s not just a rule that someone else made; using 'must' means that something matters

那不仅是其他人制订的规则； 使用“must”意味着某件事

to you.

对您很重要。

For example:

例如：

"You must be here on time, otherwise we’ll miss the start."

"You must be here on time, otherwise we’ll miss the start."

Using 'must' shows that you care about whatever you’re going to see.

使用“must”显示您在乎您 会看到的东西。

Maybe you’re going to see a concert that you’ve been looking forward to for ages,

也许您会看到一场您期盼了 很多年的演唱会，

and you’ll be really unhappy if you miss even a minute of it.

如果您错过了那怕一分钟， 您会真的很不开心。

"I must finish this work today."

"I must finish this work today."

Again, this means that I feel strongly about this.

同样，这意思我对此深有感触。

Maybe I promised someone that I would finish it by today, and it’s important to me that

也许我承诺某人我今天会完成 它，履行承诺对我

I keep my promise.

而言是很重要的。

When talking about rules, we mostly use 'must' in formal or written English.

在谈论规则时，我们在正式英语或书写 英语里大部分用“must”。

For example:

例如：

"All candidates must show valid ID."

"All candidates must show valid ID."

This is a rule probably in an examination hall, which of course is a formal setting.

这有可能是一个考试大厅的规则， 当然是一个正式的设定。

"Employees must wash their hands before working with food."

"Employees must wash their hands before working with food."

This could be from a sign in a restaurant or café.

这可能是来自一间餐厅 或咖啡馆里的标牌。

Again, this is more likely to be written than spoken.

同样，这更像是书写的， 而不是口头的。

In informal English, we mostly use the verb 'have to' to talk about rules and obligations.

在非正式英语里，我们大部分用动词 “have to”来谈论规则和责任。

To review, you can use 'must' to express an obligation if the obligation is important

要复习，您可以用“must”来表达一个责任， 如果责任对您个人而言是

to you personally, or if you want to sound more formal.

重要的，或如果您想听起来 更正式。

Part two, using 'must' to talk about prohibition.

第二部分，使用“must”来谈论禁止。

You can use 'mustn’t' to say that something is not allowed or forbidden.

您可以使用“mustn’t”来说某件事 是不被允许的或禁止的。

This is the opposite of using must to talk about obligations or rules, and is similar

这是用“must”谈论责任和 规则的反义，在意思上

in meaning.

是相似的。

Look at some examples:

看一些例子：

"You mustn’t smoke here."

"You mustn’t smoke here."

That means smoking is forbidden; it’s against the rules to smoke here.

那意思是吸烟是禁止的；它是在 这吸烟的相反的规则。

"Mobile phones must not be used while the plane is flying."

"Mobile phones must not be used while the plane is flying."

Again, this means that it’s forbidden to use phones.

同样，这意思是禁止使用电话。

'Must' expresses the idea that you don’t have a choice.

“Must”表达了您没得 选择的含义。

If you mustn’t smoke here, then it’s not OK to smoke, and you don’t have a choice.

如果您不能在这吸烟，那么吸烟是 不行的，您没有选择。

'Mustn’t' with this meaning is similar to 'can’t'.

“Mustn’t”有与“can’t”相似的意思。

With obligations and rules, we mostly use 'must' in formal or written English, and 'have

搭配责任和规则，如前所述，我们 大部分在正式英语或书写

to' in informal English, as we said before.

英语里使用“must”，在非正式 英语里使用“have to”。

However, you can use 'mustn’t' in both formal and informal English.

然而，您可以在正式和非正式 英语里使用“mustn’t”。

Part three: using 'must' to give strong advice.

第三部分：使用“must”来给出强烈的建议。

'Must' can be used to give someone advice or a recommendation.

“Must”可以用于给某人建议 或一个推荐。

For example:

例如;

"You must read this book—it’s amazing!"

"You must read this book—it’s amazing!"

"If you go to Paris, you must take a walk by the river at night."

"If you go to Paris, you must take a walk by the river at night."

"We must hire some new staff as soon as possible."

"We must hire some new staff as soon as possible."

In these examples, ''must' has a strong meaning.

在这些例子里“must”有强烈的意思。

If I say:

如果我说：

"You must read this book—it’s amazing!"

"You must read this book—it’s amazing!"

I don’t mean that you have an obligation to read it.

我的意思不是您有 要读它的责任。

I mean that I really, really recommend this book.

我的意思是我真的 推荐这本书。

In the same way, if I say:

用同样的方法，如果我说：

"If you go to Paris, you must take a walk by the river at night."

"If you go to Paris, you must take a walk by the river at night."

This is advice or a recommendation.

这是建议或一个推荐。

It doesn’t mean that it’s a rule or an obligation.

那没有它是一个规则 或一个责任的意思。

Sometimes, the meaning of 'must' depends on the context.

有时，“must”的意思取决于上下文。

For example:

例如：

"We must hire some new staff as soon as possible."

"We must hire some new staff as soon as possible."

'Must' here could mean that hiring new staff is necessary, and it’s an obligation, or

“Must”在这里可以意思是聘用新员工是 必要的，这是一个责任义务，

it could be a strong recommendation.

或者它可以是很强烈的推荐。

How do you know what 'must' means in a sentence like this?

您怎么知道“must”在像这样的 句子里意思是什么？

In a sentence like this, in a lesson, where there’s no context, you can’t say exactly

在一节课上像这样的没有上下文的 一个句子里，您不能

what 'must' means.

准确地说出“must”意思是什么。

In real life, the meaning would depend on the context: who’s speaking, what the situation

在真实生活里，意思取决于 上下文：谁在说、情形是

is, and so on.

什么等等。

When you use 'must' in this way, you can’t use the negative.

当您用这种方法来用“must”， 您不能用否定的。

There’s no way to use 'mustn’t' to give advice or make recommendations.

没办法用“mustn’t”来给出 建议和做推荐。

Only the positive form—'must'—can have this meaning.

仅仅肯定形式 — “must” — 可以有这个意思。

Part four: using 'must' to talk about logical necessity.

第四部分：使用“must”来谈论 逻辑上的必要性。

Finally, 'must' can be used to make deductions.

最后，“must”可以用于做推论。

What are deductions?

推论是什么？

Well, look at some examples, and then I’ll explain what this means:

好，看一些例句，然后我会解释 这是什么意思：

"They must be rich.

"They must be rich.

Their house is huge!"

Their house is huge!"

"It must be a difficult exam—only 10% of candidates pass."

"It must be a difficult exam—only 10% of candidates pass."

"It must have rained last night."

"It must have rained last night."

Take the first sentence:

拿第一个例句看下：

"They must be rich.

"They must be rich.

Their house is huge!"

Their house is huge!"

Do we know they’re rich?

您知道他们是富有的？

No, we don’t know for a fact.

没有，我们不知道那个事实。

But, we do know that they have a huge house.

但是，我们知道他们有很大的独立屋。

Huge houses cost a lot of money.

很大的独立屋值很多钱。

Therefore, they must be rich.

因此，他们肯定有钱。

We’re sure that they’re rich, because otherwise they couldn’t afford such a big

我们确信他们是富有的， 否则他们负担不起

house.

这一个大独立屋。

Compare:

比较：

"They must be rich."

"They must be rich."

"They’re rich."

"They’re rich."

What’s the difference?

区别是什么？

"They’re rich" is a fact.

"They’re rich" 是一个事实。

We know they’re rich.

我们知道他们是富有的。

Maybe you’re their accountant, and you know all about their financial situation.

也许您是他们的会计师，您知道 他们所有的财务状况。

Maybe they told you how much money they have directly.

也许他们直接告诉您他们 有多少钱。

Anyway, however you know, you know they’re rich.

反正，无论如何，您知道， 您知道他们是富有的。

"They must be rich" is a deduction.

"They must be rich" 是一个推论。

You don’t actually know they’re rich.

实际上您不知道他们是富有的。

You know something else; you know that they have a huge house and this makes you sure

您知道某些其他事，您知道他们有 很大的独立屋，这让您

that they’re rich.

确信他们是富有的。

Okay, let’s look at another example:

好了，我们看另一个例子：

"It must be a difficult exam—only 10% of candidates pass."

"It must be a difficult exam—only 10% of candidates pass."

Again, using 'must' expresses a deduction.

同样，使用“must”表达一个推论。

If you say this, you haven’t actually taken the exam.

如果您这么说，您实际上 没有参与测验。

You don’t know for yourself that it’s difficult.

您自己不知道它是难的。

However, you do know something else: you know that only 10% of candidates pass, and this

然而，您知道某些其他事：您知道 只有10%候选人通过了，并且这

makes you sure that it’s a difficult exam.

让您确信那是一个难的测试。

In our last example:

在我们的最后一个例句里：

"It must have rained last night."

"It must have rained last night."

Did you see it rain?

您看到下雨了吗？

No, you didn’t.

没有，您没看到。

But, you’re sure it rained.

但是，您确信下雨了。

How?

怎样确定的？

Probably, you can see that the ground is wet.

有可能，您可以看到地面是湿的。

You didn’t see or hear the rain, but you can make a deduction from what you see.

您没看到或听到雨，但是您可以从 您看到的东西做一个推论。

What you see makes you sure that it rained last night.

您看到的让您确信昨晚有下雨。

You can also use 'must not' with this meaning, but you can’t use the short form 'mustn’t'

您也能用“must not”搭配这个意思， 但是您不能在标准英语里

in standard English to express the idea of deduction.

用短写形式“mustn’t”来 表达推论的想法。

'Mustn’t' is only used to say that something is forbidden.

“Mustn’t”是仅用于说某件事 是禁止的。

Okay, that's a strange point, so let's look at our next topic, which is negatives--part

好的，这是一个奇怪的要点，所以 我们在下一个主题里来看看它，

five.

那是否定的—第五部分。

It’s important to remember that when you use 'must' with different meanings, the negative

那对记得您什么时候用有不同 意思的“must”很重要，否定

(or opposite) word is also different.

（或反义）的单词也是不同。

Okay, let's look at this.

好，我们看看这个。

So, if 'must' is used for obligation, the opposite would be 'mustn't', or maybe 'can't'.

那么，如果“must”用于责任，反义会是 “mustn't”，或者也许“can't”。

The opposite of 'mustn't' for prohibition would be 'must' or maybe 'have to'.

“mustn't”用于禁止的反义会是 “must”或也许是“have to”.

The opposite of 'must' for strong advice is 'shouldn't'.

"must"用于强烈建议的反义 是“shouldn't”。

And for making deductions, the opposite of 'must' would be 'can't', 'couldn't', or maybe

用于做推论，“must”的反义会是 “can't”、“couldn't”、或也许是

'must not'.

“must not”。

For example:

例如：

"Passengers must place bags above the seats."

"Passengers must place bags above the seats."

Here, 'must' expresses an obligation.

在这里，“must”表达一个责任。

The opposite would be:

反义会是：

"Passengers must not place their bags above the seats."

"Passengers must not place their bags above the seats."

Or, if you wanted to explain this rule in spoken English, you might say:

或者，如果您想用英语口语 解释这个规则，您可能说：

"You can’t put your bag above your seat."

"You can’t put your bag above your seat."

Another example:

另一个例子：

"You mustn’t say anything to her."

"You mustn’t say anything to her."

Here, 'must' expresses prohibition.

在这里“must”表达了禁止。

The opposite is:

反义是：

"You must say something to her."

"You must say something to her."

Or:

或者：

"You have to say something to her."

"You have to say something to her."

Finally, if you say:

最后，如果您说：

"He must be awake.

"He must be awake.

It’s two o’clock in the afternoon!"

It’s two o’clock in the afternoon!"

Here, 'must' expresses a deduction.

在这里，“must”表达了一个推论。

The opposite could be:

反义可以是：

"He can’t be awake.

"He can’t be awake.

He never gets up before the late afternoon."

He never gets up before the late afternoon."

Or perhaps:

或可能是：

"He must not be awake.

"He must not be awake.

He never wakes up early."

He never wakes up early."

It’s important to remember that these opposites are not all the same!

记住这些反义不是都是 一样的很重要！

For example, if you use 'must' to express prohibition, the possible opposites are 'must'

例如，如果您使用“must”来表达禁止， 可能的反义是“must”

and 'have to'.

和“have to”。

This doesn’t mean 'must' and 'have to' have the same meaning.

这并不意味着“must”和 “have to”有相同的意思。

Modal verbs are complicated.

情态动词是复杂的。

For now, you need to remember one important point:

至于现在，您需要记住 一个重点：

Different meanings of 'must' have different negatives.

不同意思的“must”有不同的否定。

OK?

好了吗？

Good!

好的！

Let’s look at one more point.

我们来再看一个重点。

Part six: past forms.

第六部分：过去形式。

Like with negatives, if you want to use must to talk about the past, the past form depends

像是搭配否定，如果您想使用“must”来 谈论过去，过去形式取决于

on the meaning of 'must'.

“must”的意思。

Often, you need to use a different verb.

通常，您需要使用不同的动词。

Take a look:

看一看：

So, 'must' for obligation, the past form is 'have to'.

所以“must”表达禁止，过去 形式是“have to”。

'Mustn't' for prohibition, the past form is 'couldn't'.

“Mustn't”表达禁止，过去 形式是“couldn't”。

'Must' for strong advice or recommendations, the past form is 'should have'.

“Must”表达强烈建议或推荐， 过去形式是“should have”。

And for making deductions, the past form is 'must have'.

要表达推论，过去形式 是“must have”。

Using 'must' with a past meaning is only possible if you are using 'must' to make deductions.

如果您使用“must”来做推论，使用有 过去意思的“must”是可能的。

In all other cases, you need to use a different verb to talk about the past.

在所有其他事例里，您需要使用 不同的动词来谈论过去。

Let’s look at some examples:

我们来看一些例子：

"We must be there at 9.00 tomorrow."

"We must be there at 9.00 tomorrow."

This is an obligation.

这是一个责任。

In the past, you'd say, "We had to be there at 9.00 yesterday."

在过去式，您要说："We had to be there at 9.00 yesterday."

"We mustn’t smoke in the restaurant."

"We mustn’t smoke in the restaurant."

That's prohibition.

是禁止。

The past: "We couldn’t smoke in the restaurant."

过去式： "We couldn’t smoke in the restaurant."

"You must try the stew—it’s delicious!"

"You must try the stew—it’s delicious!"

This is advice.

这是建议。

The past form: "You should have tried the stew—it was delicious!"

过去形式："You should have tried the stew—it was delicious!"

"They must be on the subway—I can’t get through on the phone."

"They must be on the subway—I can’t get through on the phone."

That's a deduction.

那是推论。

The past form: "They must have been on the subway—I couldn’t get through on the phone."

过去形式："They must have been on the subway—I couldn’t get through on the phone."

You can see how you need to use different verbs to talk about the past, depending on

您可以看到您怎样需要依据“must” 的不同意思来用不同的

the meaning of 'must'.

动词谈论过去。

Okay, finally, let's do a review.

好的，最后，我们来复习一下。

Let’s review what we’ve studied in this lesson.

我们复习在本节课学到了什么。

'Must' can be used to express obligation and prohibition, to give strong advice, and to

“Must”可以用于表达责任和禁止， 来给出强烈建议，

make deductions.

以及做推论。

In some cases, 'must' is similar to other verbs.

在一些事例里，“must”类似 于其他动词。

For example, 'must' used to express prohibition is similar to 'can’t'.

例如，“must”用于表达禁止是 类似于“can’t”。

However, remember that similar does not mean the same!

然而，记得类似并非意味着相同！

'Must' is unique, and no verb is ever exactly the same as 'must'.

“Must”是独特的，没有动词与 “must”完全相同。

Different meanings of 'must' have different negative and past forms.

“must”的不同意思有不同的 否定和过去形式。

In other words, the way you use 'must' depends on the meaning of 'must'.

换句话说，您使用“must”的方法取决于 “must”的意思。

You can’t just use 'must' in the same way in every sentence; you need to think about

您不能在每一个句子里以相同的 方式用“must”；您要考虑

what 'must' means in each case.

“must”在每个事例里的意思是什么。

Do you want more practice with this topic?

您想在这个主题有更多的练习吗？

Check out the full version of the lesson on our website: www.oxfordonlineenglish.com.

在我们的网站看课程的完整版本： www.oxfordonlineenglish.com

The full lesson includes notes and exercises to help you practise what you’ve learned

完整的课程包括笔记和练习， 帮您做与您在本节课里

in this class.

学到的相关的练习。

That’s the end of the lesson.

本节课就到这了。

Thanks very much for watching!

非常感谢观看！

I hope it was useful for you.

我希望那对您有用。

I'll see you next time!

我们下次见！

Bye bye.

再见！