* Dạng 1:
        S + HTHT (phủ định) + for + thời gian
       It’s + thời gian ….+ since …+ last + QKĐ (khẳng định)

Ex: I haven’t seen my father for one month. 

      – It is one month since I last saw my father.

      Tom hasn’t had his hair cut for over three months. 

     – It is three months since Tom last had his hair cut. 

 * Dạng 2: 
     S + HTHT (phủ định) + before
     It’s + the first time + S + HTHT (khẳng định)

Ex: I haven’t seen that man here before. 

    – It is the first time I have met that man here.

      It is the first time I have read this book. 

    – I haven’t read this book before. 

* Dạng 3:     
   -  S + HTHT (phủ định) + since / for + …..
   - S + last + QKĐ (khẳng định) …+ when + mệnh đề
   - The last time + S + QKĐ (khẳng định) + was + thời gian

Ex: I haven’t heard him since August. 

     – The last time I heard him was in August.

      I haven’t seen him since I left school. 

     – I last saw him when I left school.                                                                    

* Dạng 4:
    S + HTHT (khẳng định) + for + thời gian
    - S + began / started + V-ing + thời gian + ago

Ex: I have worked here for ten years. 

     – I began working here ten years ago.

      It started raining two days ago.   

     – It has rained for two days.

Mời bạn tham khảo ạ!

VD:This is the first time I have to see him.

  Chuyển:I have never seen him before.

Công thức:The first time + S + have/has + V3 / ed + .....

 S + have/has + never + V3/ed .... before