It is not necessary for you to buy me a present.

• You needn't buy me a present

• You mustn't buy me a present

• You have to buy me a present

• You need to buy me a present

In our school it is obligatory to wear a uniform.

• In our school you must wear a uniform

• In our school you can wear a uniform

• In our school you have to wear a uniform

• In our school you don't have to wear a uniform

It isn’t necessary for you to take a jacket.

• You must take a jacket

• You don't have to take a jacket

• You needn't to take a jacket

• You mustn't take a jacket

You aren’t allowed to talk during the exam.

• You needn't talk during the exam

• You don't have to talk during the exam

• You must talk during the exam

• You mustn't talk during the exam

It’s forbidden to park here.

• You must park here

• It need to park here

• You mustn't park here

• It mustn't park here

He is obliged to go to the police station twice a week.

• He have to go to the police station twice a week.

• He has to go to the police station twice a week.

• He must go to the police station twice a week.

• He mustn't go to the police station twice a week.

It is unnecessary for you to come.

• It is needn't for you to come.

• You have to come.

• You don't have to come.

• It doesn't have for you to come.

Eating chewing-gum in the class is prohibited.

• You don't have to eat chewing-gum in the class

• You mustn't eat chewing-gum in the class

• Eating chewing-gum in the class is must

• Eating chewing-gum in the class doesn't have to

There is an obligation to turn off the mobile phone.

• We must turn off the mobile phone

• We needn't turn off the mobile phone

• We mustn't turn off the mobile phone

• We have to turn off the mobile phone

It is necessary for me to study for the exam

• I mustn't study for the exam

• I have to study for the exam

• I needn't study for the exam

• I don't have to study for the exam