GG3 U3 7.3 Grammar must, mustn't,can

We _____ leave rubbish behind. You ______ take this with you. You _______ put it in the bin outside.

You _______ make a mess.

Before we leave the lab we ________ put the books back in their place.

• must

• mustn't

Before we leave the lab we ______ tidy up the lab desk.

• must

• mustn’t

Before we leave the lab we ______ forget to turn off the lab computers.

• must

• mustn’t

Before we leave the lab we _______ leave any rubbish on the floor.

• must

• mustn’t

Before we leave the lab we ________ turn off all the lights.

• must

• mustn’t

You _______ run in the classrooms.

You _______ be quiet during a test.

Yoy _______ fall asleep in class!