MUST/MUSTN’T
HAVE TO/DON’T HAVE TO
- Have/has to do something = it is necessary to do it. I am obliged to do it.
“You can’t turn right here. You have to turn left”
“My brother is the owner of the company. He has to make important decisions”
“I haven’t had to go to the doctor for ages”
“Why did you have to leave early?”
“She doesn’t have to work tomorrow”
“I’ve got to work tomorrow” (‘have got to’/‘has got to’ is also ok)
- Used to give your own opinion, to say what you think is necessary, or to recommend someone to do something (‘must’ can also be used)
“I haven’t spoken to Susan for ages. I have to/must call her”
“My friend is a really nice person. You have to/must meet him”
- ‘Have to’ is used instead of ‘must’ to say what someone is obliged to do. The speaker is not giving his/her own opinion.
“I have to work from 8h to 14h Monday to Friday” (a fact, not an opinion)
“My brother has to travel a lot for his work” (a fact, not an opinion)
- You don’t have to = you don’t need to do it (but you can if you want)
“You don’t have to come early. It doesn’t open until 10h”
“The car park is free. You don’t have to pay to park your car here”
Compare these two sentences:
“I don’t have any exams soon, so I don’t have to study” – you don’t need to do it but you can if you want.
“I must study hard if I want to pass my exams” – I think it’s necessary if I want to pass my exams.