Must is used to say someone has to do something. It shows a strong rule or need. It is very common in daily life.
You must wear a seatbelt.
Students must study for tests.
Must is used when we are sure about something. We believe it is true based on evidence.
He must be at home now.
That must be the answer.
Must is used to give advice. It shows things that are very good or important to do.
You must try the chocolate cake.
This book must be read by all.
Must as a noun means something very important or needed. People say it about things you must have or do.
Food and water are a must.
A ticket is a must for the show.
Must is used to talk about things that are very popular or important in fashion or current trends.
This dress is a must this summer.
Smartphones are a must now.
Must can be a verb that means to give a strong, often bad, smell or taste. It is used with food or drink that goes bad.
The cheese musted in the warm room.
The old wine musted quickly.
