Must / Mustn't", "have to" / "don't have to", "should"

What does 'must' express?

• optional or discretionary

• necessity or requirement

• forbidden or prohibited

• possibility or choice

What does 'mustn't' express?

• prohibition or strong recommendation

• permission

• suggestion

• obligation

Fill in the blank: You _______ wear a helmet while riding a bike.

• must

• might

• should

• can

Fill in the blank: You _______ talk in the library.

• shouldn't

• have to

• can

• must not

Choose the correct sentence: a) You mustn't eat too much candy. b) You must eat too much candy.

• You must eat too much candy.

• You mustn't eat too much candy.

• You shouldn't eat too much candy.

• You should eat too much candy.

Choose the correct sentence: a) I mustn't forget my keys. b) I must forget my keys.

• a) I mustn't forget my keys.

• c) I should forget my keys.

• b) I shouldn't forget my keys.

• a) I must forget my keys.

Create a sentence using 'must' to express obligation.

• You must never brush your teeth.

• You must always wear a hat indoors.

• You must finish your homework before going out to play.

• You must eat ice cream for breakfast every day.

Create a sentence using 'mustn't' to express prohibition.

• You mustn't wear a hat indoors.

• You mustn't cross this line.

• You mustn't drive without a license.

• You mustn't eat that cake.

When do we use 'must' in a sentence?

• To indicate a past action

• To show uncertainty

• To express a mild suggestion

• To express a strong obligation or necessity.

When do we use 'mustn't' in a sentence?

• To express permission or possibility.

• To express prohibition or strong advice.

• To indicate obligation or necessity.

• To convey uncertainty or doubt.