3 Complete the words.

Solution:

1. sad = unsad
2. wrong = inwrong
3. you can't do it = impossible
4. relaxed and friendly = unrelaxed and friendly
5. not follow the usual rules = irregular
6. criminal = illegal
7. strange = unstrange
8. you can't see it = invisible

Answer: unhappy, incorrect, impossible, unfriendly, irregular, illegal, unusual, invisible.