Correct the answer

Dear Student,
The answers are:
1. Sarah was not allowed to sit in the examination for being absent without leave.
2. I was very happy with the gift Sandhya sent me yesterday.
3. I must perform the duties which I have.
4. He went to the hospital being injured in an accident.
5. I am pleased to announce that he has won the first prize.
6. The train will stop if you pull the chain.
7. Arjun must not play cricket yet because he is still very weak.

Hope this helps.

Regards