`1.` This is the first time I have ever been to Sa Pa.

`->` Cấu trúc :

       This is the first time + S + have/ has + V2

`=` S +have/ has + never + V2 + before

`=`  This is (It is) the most + Adj/ Adj + est + N + S + have/ has ever + V2

`2.` I haven't seen him since 2010.

`->` Cấu trúc :

The last time + S + V2 was + khoảng thời gian + ago

`=` S + last +V2+ khoảng thời gian + ago

`=` S + have/ has not = haven't/ hasn't + V2 for + khoảng thời gian

`=`  It's + khoảng thời gian + since + S + V2

`3.` It's the most amazing sight she has ever seen.

`->` Tương tự cấu trúc câu `1`

`4.` The weather in Sydney isn't as hot as the weather in Rio de Jainero.

`->` So sánh ngang bằng

`5.` They have lived in New York since 2004.

`6.` The last time we went to Ha Noi was three years ago.

`->` Tương tự cấu trúc câu `2`

`7.` Big Ben is the most famous tower in England.

`->` So sánh nhất

`8.` New York is morderner than London.

`->` So sánh hơn 

1 . This is the first time I have ever been to Sa Pa

2 . I haven't seen him since 2010

3 . It's the most amazing sight that she has ever seen 

4 . The weather in Sydney isn't as hot as the weather in Rio de Janeiro 

5 . They have lived in New York since 2004

6 . The last time we went to Ha Noi was three years ago

7 . Big Ben is the most famous tower in England

8 . New York is more modern than London