(Cong thuc trong hinh); S + started/ began + to-V/ V-ing ... = S+ have/ has + P2...
1. We started to learn English 10 years ago
2. We haven't met for a long time
3. It's 4 years since Ms. Ann last took part in any voluntary programs
4. It's when last Christmas since I last met my family
5. How long is it since you lived here?
How long is it since + S + V-ed..? = How long have/has + S + P2..?
6. The volunteers began providing free food and fresh water to homeless people yesterday
7. The doctor started to quit his job in the local hospital and moved to the central hospital 2 days ago
8. It's when last year since the children last had a long vacation
9. The last time they visited their parents was 3 months ago
10. We have broken up for 2 years