I can't give you any more help for two immediate reasons.
1. The course provider may be using this assignment to judge whether your command of English grammar is sufficient for you to be accepted on the course. For us to help you would be wrong.
2. You may have an interview, face-to-face or on the phone, and the interviewer may want to discuss some of your answers with you. S/he wants your reactions to the problems, not ours.
Do not worry. The answers you have given so far suggest to me (a former trainer) that you have the knowledge and common sense to show the course providers that you are the type of applicant who has the potential to complete the course successfully. They don't expect you to know everything before you start!
- For Teachers