1.But for his encouragement , they wouldn’t have been successful.
-> If it hadn't been for his encouragement , they wouldn’t have been successful.
But for + N/V-ing, S + would/could/might/… + have PII
= If it hadn’t been for + N/V-ing, S + would/could/might/… + have PII
2. Experts think that all dogs evolved from wolves. (descended)
-> All dogs are thought by experts to have descended from wolves.
Desscended from: xuất thân từ