=>
1. We haven't seen the film for 10 years.
2. My sister has taught at this school since 1998.
3. I haven't written to my parents for a long time.
4. We haven't seen our grandfather for five months.
5. We haven't seen her since we left university.
6. Minh has collected stamps since 2000.
7. My sister has learned English for 5 years.
8. They have used that computer for three months.
9. We haven't gone to Hue for nearly two years.
10. I haven't visited my parents since Monday.
Chuyển từ QKĐ sang HTHT : S have/has (not) V3/ed
for + khoảng thời gian
since + mốc thời gian