Grammar Rule

Examples

I must do my homework.You mustn’t be late for class.We must wear our school uniform.

Remember!

We can use ‘must’ to talk about rules. For the negative, we can say ‘must not’ or ‘mustn’t’.
Parents must take care of their children.You mustn’t shout in the library.She must not forget her books.

Be careful!

The main verb is without ‘to’.
He must be careful when cutting food.I mustn’t make a mess.

We say... We don’t say...

You must look both ways when crossing the road. (NOT You m̶u̶s̶t̶ ̶t̶o̶ look both ways when crossing the road.)

We mustn’t run in school. (NOT We m̶u̶s̶t̶n̶'̶t̶ ̶t̶o̶ run in school.)

Children must respect their parents. (NOT Children m̶u̶s̶t̶ ̶r̶e̶s̶p̶e̶c̶t̶i̶n̶g̶ their parents.)

Using Must & Mustn't in dialogs

Exercise on MUST & MUSTN'T
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