1. The blue clock isn't as new as the red one.

- A + so sánh hơn + B = B + be not + so sánh bằng + A.

2. The Fansipan is the highest mountain in Viet Nam.

- No + pronoun + so sánh hơn + S = S + so sánh nhất.

3. Sydney Street isn't as long as Oxford Street.

4. This is the first time I've ever visited such a beautiful sight.

5. My sister will eighteen next week.

1.The blue clock is older than the red clock.
2.The Fansipan is the highest mountain in the Vietnam.

3.Sydney Street is shorter than Oxford Street.

4.This is the first time I have ever visited such a beautiful sight.

5.My sister will  eighteenthin her birthday.

                       Chúc bạn học tốt !
                        @Cloud