Vocabulary: verbs ‘must’ and ‘have to’
Pre-intermediate level (A2/B1)

Here are some of the rules for the staff at 2 companies using ‘must not’ and ‘don’t have to’:

Company A

• You must not use your computer to look at Facebook (no choice)
• You must not arrive more than 5 minutes late without a good reason (you need a good reason)
• You must not wear brown shoes at any time (not allowed)

Company B

• Men do not have to wear a tie on Fridays (you can choose)
• You do not have to explain why you are late (we trust you)
• You do not have to work fixed hours (you can choose)

Which company would you like to work for? Well, company A is very strict and company B gives you a lot more freedom. Confusing ‘must not’ and ‘have to’ is a very common mistake for learners of English and completely changes the meaning.  

Pronunciation

When speaking normally ‘must not’ is pronounced as one word  and sounds like ‘musnt’.