ta có cấu trúc thì QKĐ 

động từ to be 

+ : S + was/ were +…

động từ thường

+ : S + V-ed +…

1 when did you buy that table 

-> thì QKĐ 

-> sau did + v nguyên mẫu 

2 how much did your computer cost 

-> thì QKĐ 

-> sau did + v nguyên mẫu 

3 what did you do after school yesterday ? 

-> yesterday là dấu hịu nhận bt của thì QKĐ 

4 Why didn't you call me yesterday ? 

5 where did david save his photos on the computer ? 

6 which flies did you delete ? 

7 how many copies did david print yesterday ? 

8 which company did steve jobs help to start ?

Bài 2

attach -> attching 

tie -> tying

run -> running

save -> saving

give -> giving

get -> getting

delete -> deleting

change -> changing

upload -> uploading

think p> thinking

win -> winning 

spot -> spoting 

serve -> serving 

realise -> realising