1. You did these exercises well
2. You must wash this dress in cold water
3. He hasn't made any mistakes in his composition
4. New Arts gallery will exhibit his painting for the first time
5. They built this house 100 years ago
7. The students are writing the lessons now
9. They feed these animal at the zoo twice a day
10. French doctors are going to perform the operation
13. No one could find them
15. The accident didn't damage the machinery
20. It is said that apples are good for our health
21. Don't let the children tease the dog