must\mustn't
You must or must not take a picture in the musuem.
You must not take a picture in the musuem.
You always should or should not use the utensils properly, and you should or shouldn't chew with your mouth opened.
You always should use the utensils properly, and you shouldn't chew with your mouth opened.
We don't have to\have to wear a uniform.
We have to wear a uniform.
You must or must not cross the road when the light is red.
You must not cross the road when the light is red.
You should or should not use your phone or electronic devices, especially during the conversation.
You should not use your phone or electronic devices, especially during the conversation.
To win you have to or don't have to score more goals than that of your opponents.
To win you have to score more goals than that of your opponents.
You must or must not follow the school rules.
You must follow the school rules.
You should or shouldn't push in your chair when you leave the table.
You should push in your chair when you leave the table.
You have to or don't have to follow the rules in the library.
You have to follow the rules of Apple Tree.
To score, the ball must or must not go into your opponent's goal.
To score, the ball must go into your opponent's goal.
You should or shouldn't give advice unless someone asks for it.
You shouldn't give an advice unless someone asks for it.
It's Sunday tomorrow. I have to or don't have to wake up early tomorrow for school.
I don't have to wake up early tomorrow for school.
Parents must or must not take care of their children.
Parents must take care of their children.
You should or should not reach across the table to sample your companion's food.
You should not reach across the table to sample your companion's food.
We have to or don't have to finish project by Friday.
We have to finish project by Friday.