C) Use MUST / MUSTN'T HAVE TO or (NOT) HAVE TO:
1. I can stay in bed tomorrow morning because .......... work
2. Whatever you do, you.......................
touch that switch. It's very dangerous.
3. You ........................forget what I told you. It's very important.
4. We................................leave yet. We've got plenty of time.
5. Ann was feeling ill last night. She ....................................leave the party early.
6. I.......................................go to the bank yesterday to get some money.
7. The windows are very dirty. I.................................clean them.
8. The windows aren't dirty. You .......................................clean them.

D) Fill in the blanks using (NOT) HAVE TO / MUST (NOT) / CAN / COULD:
1. George has traveled a lot. He...................speak four languages.
2. I can't sing now but I..........................
sing very well when I was a child.
3. She will stay in bed till 10 o'clock this morning. Because she......................go to work.
4. Many students in Turkey......................
wear uniform when they go to
school.
5. I'm sorry I couldn't come yesterday. I .................................work late.
6. You've been coughing a lot recently. You...............................smoke so much.