1. As she wasn't at college yesterday I couldn't speak to her. 2. Ask him whether he goes in for sports. 3. Mark was waiting until they arrived. 4. I am sure that you are wrong.…

Here are the sentences corrected for grammar and clarity:

1. Since she was not at college yesterday, I couldn't speak to her.
2. Ask him if he participates in sports.
3. Mark was waiting for them to arrive.
4. I am certain that you are mistaken.
5. Please tell me where we are going.
6. The teacher stated that honesty is the best policy.
7. We eat in order to live.
8. We visited the castle that was talked about so much.
9. Jeremy started going to school when he was five years old.