EXPRESSING OBLIGATION «MUST»

You must study hard to pass your class.

It is cold. You must put on your coat.

My grandfather is very ill. He must see a doctor.

This book is great. Everybody must read it.

This ice-cream is wonderful. She must taste it.

EXPRESSING PROHIBITION «MUSTN’T» You mustn’t go to bed late.

Your father is driving very fast. He mustn’t drive fast.

You mustn’t talk in the library.

We mustn’t pollute the environment.

Rewrite the sentences using must / mustn’t 1. Don’t use pesticides on farms. We mustn’t… 2. Don’t destroy rainforests. 3. Use solar energy.

4.Don’t use fossil fuels. 5. Save water and energy. 6. Recycle paper, bottles and glass.

Write sentences with «must» and «mustn’t» Bob is overweight. (go on a diet/ eat fast food) What must he do? What mustn’t he do?

The children are in the library. ( be quiet / make noise)

The students are having an exam. ( answer all the questions / cheat)

Susan is driving. ( obey the rules / drive fast)

Tony and Jack are playing volleyball Tony and Jack are playing volleyball. ( pass the ball over the net / touch the net)

You are in the forest. ( cut down trees / make a fire)

Are you environmentally-friendly?

must or mustn’t 1. We __________ throw bottles in the recycling bin. 2. We __________ turn of the tap when we don’t need water. 3. We __________ protect the environment. 4. We __________ leave the television on all the time. 5. We __________ use solar energy. 6. We __________ recycle paper, bottles and glass. 7. We __________waste water or electricity. 8. We __________ walk to the places nearby. 9. We __________ pollute the environment. 10. We __________ prefer public transportation. 11. We __________ cut down trees. 12. We __________ waste materials and natural resources.

Fill in the blanks with must/mustn’t and a verb plant / recycle / use / turn off / cut down/ pollute / use / throw 1. We _______________ environment-friendly perfumes. 2. We _______________ our environment. 3. We _______________ the tap while we are brushing our teeth. 4. We _____________ the materials like paper, glass and plastic. 5. We _______________ rubbish into sea. 6. We _______________ the trees. 7. We _______________ new trees. 8. We ________________ solar energy.