Intonation and pronounciation "Present perfect"

1. I've sealed the envelope
2. I've had very little vacation
3. I've preventive an accident
4. I've never tried to write verse
5. I've read Volume 1
6. I've just left my favorite class
7. I've developed several vices
8. I've spilled gravy on my test
9. I've never even seen it
10. I've lost some valuable papers
11. I've never driven a Cadillac
12. I've learned all vowels are voiced