Must (subjective obligation)
We often use must to say that something is essential or necessary, for example:
Structure of Must
Must is a modal auxiliary verb. It is followed by a main verb. The structure is:
subject + must + main verb
The main verb is the base verb (infinitive without "to").
Use of Must
In general, must expresses personal obligation. Must expresses what the speaker thinks is necessary. Must is subjective. Look at these examples:
- I must stop smoking.
- You must visit us soon.
- He must work harder.
In each of the above cases, the "obligation" is the opinion or idea of the person speaking. In fact, it is not a real obligation. It is not imposed from outside.
Must not, Mustn't (prohibition)
We use must not to say that something is not permitted or allowed, for example:
- Passengers must not talk to the driver.
Structure of Must not
Must is an auxiliary verb. It is followed by a main verb. The structure for must not is:
subject + must not + main verb
The main verb is the base verb (infinitive without "to").
Use of Must not
Must not expresses prohibition - something that is not permitted, not allowed. The prohibition can be subjective (the speaker's opinion) or objective (a real law or rule). Look at these examples:
- I mustn't eat so much sugar. (subjective)
- You mustn't watch so much television. (subjective)
- Students must not leave bicycles here. (objective)
- Policemen must not drink on duty. (objective)
We can use must not to talk about the present or the future:
- Visitors must not smoke. (present)
- I mustn't forget Tara's birthday. (future)
We cannot use must not to talk about the past. We use other structures to talk about the past, for example:
- We were not allowed to enter.
- I couldn't park outside the shop.
1.-No Smoking
2.-No running
3.-Do not yell
4.-Do not bring children
5.-Do not push
6. Please turn off cell phones.
7. Entre Are Visiting hours 3:30 and 7:30 pm.
8. No Unauthorized entry.
9. Wash your hands.
10. No more Than two visitors at a time.
