Correct the mistakes in exercise 30.

Exercise 30: Correct the mistakes.

• 1. They usually start work at 9 o'clock.
• 2. Look! That man has blue hair!
• 3. Are you studying for your exams at the moment?
• 4. I was late for work yesterday morning.
• 5. Dave has planned his holiday since Christmas.
• 6. Sheila has typed twenty letters so far this morning.
• 7. The sun has been setting in the west.
• 8. We were sleeping for an hour when the phone rang.
• 9. Lydia had been buying a new car last month.