21. was
yesterday → QKĐ
22. bought
last week → QKĐ
23. plays
every Sunday → HTĐ
24. have
every year → HTĐ
25. goes
often → HTĐ
26. circles
Điều hiển nhiên → HTĐ
27. don't have
every morning → HTĐ
28. didn't do
last night → QKĐ
29. Did, live
five years ago → QKĐ
30. washes
every day → HTĐ
Cấu trúc thì hiện tại đơn:
*Động từ thường:
(+) S + V_inf/ V-e,es
(- ) S + don't/ doesn't + V_inf
(? ) Do/ Does + S + V_inf?
*Động từ tobe:
(+) S + is/ am/ are + ...
(- ) S + is/ am/ are + not + ...
(? ) Is/ Am/ Are + S + ...
Cấu trúc thì quá khứ đơn:
*Động từ thường:
(+) S + V_ed/ V2
(- ) S + didn't+ V_inf
(? ) Did + S + V_inf?
*Động từ tobe:
(+) S + was/ were + ...
(- ) S + was/ were + not + ...
(? ) Was/ Were + S + ...
