giúp mình với ạ cần gấp

6. I was sent this letter by Mary two days ago
7. Compost made from vegetables.
8. This work must be finished before Sunday.
9. This bicycle hasn't been used by her for a long time.
10. A strange man was seen in my garden yesterday.
11. The floor is cleaned by them every morning.
12. The problem will be solved by them soon.
13. The glass is broken into small pieces by them.
15. These cars were made in the USA.
16. The internet has been used all over the world.