Ex.4: 1. B 2. A 3. C 4. A 5. B 6. B 7. A 8. C 9. A 10. A 11. C 12. A 13. B 14. A 15. B
Ex.5: 1. learning 2. love 3. four 4. making 5. problems 6. teacher 7. subjects 8. boring 9. water 10. summer
Ex.6: 1. midnight 2. English 3. obey 4. streets 5. slaves 6. return