Circle the mistake in each sentence. Then correct it.
1. (A) Despite my grandfather has (B) retired, he still works (C) as a volunteer teacher (D) in the local school.
2. I (A) quitted my previous (B) job (C) so it was so (D) tiring.
3. I decided to (A) join the English club (B) such that I can (C) practise my English (D) more frequently.
4. (A) The job will give you (B) not only a good salary (C) but a good chance for (D) promotion.