1. She started teaching english 4 years ago.
She has taught English for 4 years. ( HTHT ⇒ QKĐ )

- Công thức :

 S + started/ began + V-ing/ to-V +     t/gian + ago

                                                               in/ on/ at + t/gian

                                                               When + S + V

 S + have/ has + V(ed/3) ... +     for + t/gian

                                                   since + t/gian

                                                   since + S + V

2. My brother last ate cakes in 2014.

   My brother hasn’t eaten cakes since 2014. ( HTHT ↔ QKĐ )

- Công thức : 

  S + last + V(ed/2) +     t/gian + ago
                                       in/ on/ at + t/gian
                                       When + S + V

S + have/has + not + V(ed/3) +     for + t/gian
                                                        since + t/gian
                                                        since + S + V

5. When did they begin buying food ?
   How long have they begun buying food ? ( HTHT ↔ QKĐ ) 

- Công thức : 

  When + did + S + V(nt) ?

= How long + have/ has + S + V(ed/3) ?

6. If she doesn’t catch a bus, she will be late for work.
   Unless she catches a bus, she will be late for work.

- Unless = If not 

 Ta chỉ cần bỏ not ở vế đầu .

7. Get up early or you are late.
   If you don't get up early, you will be late. ( câu đk loại 1 )

8. He hasn’t met us in the park before.
  It is the first time he has met us in the park. ( HTHT ↔ QKĐ )

- Công thức :

   It/ This + is the first time + S + have/ has + V(ed/3)

   S + have/ has + never/ not + V(ed/3) ... + before

9. My sister is going to draw me a portrait tomorrow.
   I am going to drawn a portrait by my sister tomorrow.

- Chuyển sang câu bị động với động từ khuyết thiếu " is going to "

10. Nobody drives a car to work in the street.
     A car isn't driven to work in the street.

- Chuyển sang câu bị động thì HTĐ

11. He wrote her an email in English 
     She was written an email in English ( by his ).

- Chuyển sang câu bị động thì QKĐ

12. Are your children listening to music now?
     Is music being listened to by your children now ?

- Chuyển sang câu hỏi bị động thì HTTD 

13. I have already sold an old house.
     An old house has already sold ( by me ) .

- Chuyển sang câu bị động thì HTHT

14. Be quick and you catch up him
     If you are quick, you will catch up him.

15. Will your brother eat a bowl of noodles tonight?
     Will a bowl of noodles be eaten by your brother tonight ?

- Chuyển câu hỏi sang bị động thì TLĐ