1. 18-year-olds are allowed to work.
2. No need to be so strict with your kids.
3. Your father looks upset. So he does.
4. I was born on a rainy morning.
5. The teacher is quite strict with them in studies, and they have to do as required.
6. Several days ago, I put an end to my part-time job which lasted one month.
7. I could have been a volunteer for Olympics Games. (should have done是本应该做什么事但没做,这里与中文不符,所以改用could have done)