2. I'm staying in a hotel near the sea. ("stay at" and "stay in" are practically the same in this case. both are correct.)

3. I'd like to buy this coat. How much does it cost?

4. What are you doing?

5. I usually get up at 6:00.

6. This book is difficult. I don't understand it.

7. I watch a lot of TV every night.

8. Excuse me. Do you know the way to the museum?