$\text{Cấu trúc:}$
$\text{for + khoảng thời gian (for 2 weeks, for ten years,...)}$
$\text{since + mốc thời gian trong QK (since 2000, since last year, since 3 weeks ago,....)}$
$\text{since + một hành động nào đó xảy ra trong QK}$
$\text{1. for}$
$\text{2. since}$
$\text{3. for}$
$\text{4. since}$
$\text{5. since}$
$\text{6. for}$
$\text{7. for}$
$\text{8. since}$
$\text{9. since}$
$\text{10. since}$
$\text{11. for}$
$\text{12. since}$
$\text{13. for}$
$\text{14. since}$
$\text{15. for}$
$\text{16. since}$
$\text{17. for}$
$\text{18. for}$
$\text{19. since}$
$\text{20. for}$