Error Identification — XAT Previous-Year Questions

Which of the following sentences are grammatically CORRECT?

1. Have you any clothes to dispose of?
2. I saw a pleasant dream last night.
3. I have done it many a times safely.
4. Students struggle to cope up with academic pressure.
5. You need not give negative feedback to your employees.
6. My friend is good at playing football.

Which of the following sentences have INCORRECT usage of preposition?

1. The manager was sitting at the desk.
2. My work is superior to yours.
3. I prefer coffee than tea.
4. She was accused for stealing gold.
5. This is an exception to the rule.
6. They are leaving to England soon.