`1.` Mary has been playing the piano for 4 years.

`->` HTHTTD : S + have/has + been Ving

`2.` It's 5 years since my father last went to Ha Noi

`->` It's + thời gian + since + S + (last) + Ved

`3.` My father has been reading a newspaper for 2 hours.

`->` HTHTTD : S + have/has + been Ving

`4.` I last wrote to her 4 years ago.

`->` S + last + Ved .....

`5.` It is over a year since since I last went to see them.

`->` It's + thời gian + since + S + (last) + Ved

`6.` The last game is not as exciting as this game.

`->` SS bằng : S + be + as + adj + as + S 

Các công thức đổi HTHT - QKĐ

Structure 1: 

S + has/have + not + V3/ed + for/since + time 

--> S + last + V2/ed 

--> The last time + S+ V2/ed + was + time 

--> It is / has been + time + since + S+ (last) + V2/ed 

Structure 2:

S + has/have + V3/ed + for/since + time 

--> S + started / began + to V / Ving 

--> It is / has been + time + since + S+ V2/ed 

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1. Mary has played the piano for 4 years.

2. It's 5 years since my father last went to Hanoi.

3. My father has been reading for 2 hours.

4. I have written her for four years.

5. It's over a year since I last went to see them.

6. The last game is more boring than this one.

S + be + more + ADJ + than + O : so sánh hơn

`color{orange}{~LeAiFuRuiHuiBao~}`