Chuyển câu bị động thành câu chủ động

1. These artificial flowers are made of silk

2. When was this radio manufactured?

3. Please wait here while your luggage is being examined

4.For a long time the earth was believed to be flat

5. Apples are said to be good for our health

6. What have been done to help the poor in this city?

7. The jewelry must have been stolen while she was out