1 did
-> thì QKĐ : s + v-ed / v2
-> dấu hiệu : yestreday
2 have - gone
-> thì HTHT dạng nghi vấn : have / has + S + VPII
3 visited
-> thì QKĐ : s + v-ed / v2
-> dấu hiệu : two weeks ago
4 didn't help
-> thì QKĐ dạng phủ định : s + didb't + V nguyên mẫu
5 weren't
-> thì QKĐ dạng phủ định thể tobe : s + weren't / wasn't
-> dấu hiệu : last weekend
6 did - design
-> thì QKĐ dạng nghi vấn : did + s + V nguyên mẫu
7 didn't crash
-> thì QKĐ dạng phủ định : s + didb't + V nguyên mẫu
8 took off
