1. I am bad at singing.2. He has been waiting for me, when I came.3. Who does this attemp belong to? (To whom does this attemp belong? )4. I am interested in this community.5. She is waiting impatiently for this event.6. I had watched the TV before you came. 7. Who are they waiting for.8. What do you think about this movie? 9. I thanked my friends for their help.10. I am proud of my school grades.11. I am looking for key and I can\'t find it. 12. Why are you looking at them?13. Could you watch over my dog?14. I am bad at playing football.15. I have paid for my supper.16. Who do these words belong to? (To whom do these words belong?)17. Why are you looking for your backpack?