must - mustn't

You __________ your teeth after meals.

• mustn't brush

• must help

• must brush

You __________ coffee before you go to sleep. Have some water!

• mustn't drink

• must drink

• must boil

You __________ fruit and vegetables to be healthy.

• mustn't buy

• must clean

• must eat

• We must eat in class.

• We mustn't eat in class.

• We mustn't cook in class.

• We must use mobile phones in class.

• We mustn't turn off mobile phones in class.

• We mustn't use mobile phones in class.

• You must drop litter on the floor.

• You must clean your bedroom.

• You mustn't drop litter on the floor.

• You mustn't eat too much chocolate. It's not good for you.

• You must eat too much chocolate. It's not good for you.

• You mustn't wash too much chocolate. It's not good for you.

• We mustn't wash our hands before eating.

• We must play with soap before eating.

• We must wash our hands before eating.

• You must copy during an exam.

• You mustn't copy during an exam.

• You must study during an exam.

• We must play in class.

• We mustn't participate in class.

• We must participate in class.