Hello everyone and welcome back to my channel, Sparkle English, where I teach you how to improve
your level of English. Today's lesson is a lesson on the modal verb must or mustn't. If you want
more lessons on modal verbs, click on the link in the description below this video to see my
other lessons. So we use must or mustn't to talk about rules and obligations. Must is a modal verb.
Modal verbs are followed by an infinitive without to. In affirmative sentences, we use must when
we mean that something is necessary. So, we begin with the subject and then the modal verb. I must,
you must, he, she, it must, we must, they must. Note that we do not add an s after must in the
third person singular form. So for example, you must do your homework that means it is necessary.
You have to do your homework. In the affirmative form, must is very similar to have to except it is
even stronger. You have to do your homework means it's important that you do your homework and you
must do your homework means it is necessary. It is your obligation, but they are both very
similar. I must pay my taxes before the end of the month. He must wear a seatbelt while driving.
Note that we do not have the infinitive before the verb. We don't say you must
to do your homework. We just say you must do without to. Here are the different uses of must.
We often use must to express obligation or duty. This also refers to laws and rules. For example:
you must be 16 to learn to drive a car in Ontario. We must pay rent at the beginning of every month.
We also use must to emphasize the importance of something or to give a strong recommendation.
For example, Brad must quit smoking. It's so bad for his health. You must see the new James
Bond movie. It's so good. In this example, it's not an obligation that you see the James Bond
movie. However, it is a strong recommendation. I really liked this movie. I strongly recommend
you watch the new James Bond movie. We can also use must to deduce that something is true based
on evidence. For example, they are wearing winter coats in their vacation photos. It must be cold
there because I have the evidence in the photos of these people wearing winter coats. I can
conclude that it must be cold there. Jesse must be awake. I hear someone walking around upstairs.
Again, I hear noises in Jesse's bedroom. So I can make the assumption that he must be awake.
Now mustn't equals must not. Mustn't is the contraction for must not. Mustn't expresses
prohibition. This means that something is not allowed or not permitted. For example,
we mustn't take pictures in the cathedral. This means we are not allowed or not
permitted to take pictures. You mustn't text on your phone while driving. This again
means you are not allowed and are not permitted to text while driving. It is forbidden
or in this case illegal. Now in the negative form, mustn't does not mean the same thing
as don't have to. These have very different meanings. If I say you mustn't come to my
house tomorrow, that means you are not allowed and not permitted to come to my house. If I say you
don't have to come to my house, that means it's optional. You can come but it's not obligatory.
You don't have to if you don't want to, so mustn't and don't have to have very different meanings.
So let's look at all three forms of must together. First, we have the affirmative form.
Example, I must quit eating so much sugar. You must bring your own lunch to the park. Now we
have the negative form. I mustn't eat so much sugar. You mustn't forget to bring your own lunch.
And finally, we have the interrogative form with the interrogative form. And with modal verbs,
we begin with the modal verb to form a question. So for example, must I? Must you? Must he?
And this is another way of asking, is it necessary? Must you quit eating sugar? This means
is it really necessary that you quit eating sugar? Do you have to? Must I bring my own lunch to the
park? Is it really necessary that I bring my own lunch? Okay, so now we're going to do a practice
quiz on must or mustn't. You have to tell me if these sentences are correct or incorrect?
Number one. Do we must wear a seatbelt? Number two, you must try this new restaurant.
Number three, she musts be tired after that long flight. Number four, he mustn't eat so much sugar.
Number five. Must we bring drinks to the party? Number six, he must to brush his teeth before
bed. And finally number seven. Jane doesn't must smoke in the building.
Okay, so let's correct these together. Number one is incorrect. Do we must wear a seatbelt?
When we form questions with modal verbs. We begin with the modal verb we do not
use do. So in this example, we start with must, then we have the subject. Must we wear a seatbelt?
Is it necessary that we wear a seatbelt? Number two is correct. You must try this new restaurant.
That is correct. Number three is incorrect. She must be tired. We do not add an s after a modal
verb. It stays the same for all subjects. So the correct answer is she must be tired
after that long flight. Number four is correct. He mustn't eat so much
sugar. Number five is also correct. Must we bring drinks to the party? This is correct.
Number six is incorrect. We have an extra word. He must to brush his teeth before bed.
We do not have to before the verb we just have the infinitive. He must brush his teeth before
bed. And finally number seven is incorrect. Jane doesn't must smoke in the building.
To make a modal verb negative. We don't use doesn't or don't. We say mustn't or must not.
Jane mustn't smoke in the building. So let me know in the comment section how many you got correct
out of seven. If you've got less than five, I recommend you watch this video again and take the
quiz a second time. I'd also like you to practice talking about your responsibilities using must or
mustn't. Do you have duties or obligations? What are two things you must do? What are two things
you mustn't do? For example, I must feed my dog twice a day. I mustn't drive without my glasses.
Let me know in the comments section some things that you must or mustn't do in your
life. Thank you guys for watching. Make sure to subscribe to Sparkle English for
more lessons on how to improve your level of English. And I will see you in my next lesson.