`1.` The last exhibition was not as interesting as this one.

`-` So sánh hơn :

`->` S + to be + as + adj (tính từ) + as + O
`2.` The teacher says that I'm the noisiest student in the school.

`-` People (they; some one) + say (said) + that + S₂ + V₂ + O₂
`3.` I have never read a book less interesting than this one.

`-` S + have + never + V_inf 

`-` S + V + Less + Adj + than + N/P
`4.` I think there is no city more livable than Paris in the world.

`-` S+think+mệnh đề: "ai đó" nghĩ rằng...
`5.` This city hasn't changed since the `1990s.`

`-` S + have/has + V-ed + since +....
`6.` He felt that the visit to the gallery was quite exciting.

`-` Felt + (that) +...: cảm thấy rằng/nghĩ rằng

`-` S + was/ were +…

1. The last exhibition was not as interesting as this one

- Vì câu gốc: Cái triễn lãm này thú vị hơn triễm lãm hồi trước -> Triễn lãm hồi trước không thú vị bằng

- So sánh bằng: tobe (not) + as + adj + as

2. The teacher says I'm the noisiest student in the school

- No one/.... + tobe + comparative adj + than + s.one = S.one + tobe + the + superlative adj + ...

- Những tính từ 2 âm tiết kết thúc bằng -y,-et,-le,-ow,-er sẽ thêm -est 

- Noisy biến -y -> -i và thêm -est

3. I have never read such a boring book like this before

- least interesting -> most boring

- S + have/has + Vp.p + such + adj noun + (like this/...) + before

4. I think there is no place  in the world more liveable than Paris

- No one/.... + tobe + comparative adj + than + s.one = S.one + tobe + the + superlative adj + ...

5. This city hasn't changed anything since 1990s

- vẫn y nguyên -> không thay đổi

- since + mốc thời gian

6. He felt it was quite exciting to visit to the gallery

- It + tobe + adj + to do s.th