Question

Change the voice
10. He snapped open the cover.
11. I went back to my stamps.
12. The postmark proves the date.
13. They're never opened.
14. I found the third level.
15. I'm invited over for lemonade.​

Answer 1

Answer:

the cover open was snapoed by him

My stamps were gone back by me

the date is proved by the postmark

Let them not to opened

the third level was found by me

over for lemonade was invited by me

hope it is helpful to you