1. People won't use flying cars until the year 2050.

- " until the year 2050" DHNB thì Tương lai đơn
+ Cấu trúc: (-) S + won't + V_nguyên mẫu

2. A hydropower station will be built in the North of the country next year.

- " next year" DHNB thì Tương lai đơn
+ Cấu trúc câu bị động: S + will + be + Ved/V3

3. The countryside has less pollution than big cities.

+ Cấu trúc thì HTĐ: S + Vs/es

- less + N(ko đếm được)

4. They prefer to go in their car than on the train.

-> prefer + to + V_nguyên mẫu

1.People won't use flying cars until the year 2050 

2.A hydropower station will be built in the North of the country next year 

3.The countryside has less pollution than big cities 

4.They prefer to go in their car than on the train 

Giải thích : 

1.Until the year 2050(dấu hiệu chia TLĐ) 

2.Next year(TLĐ);hydropower station(chỉ vật) 

3.Dịch 

4.Form : prefer +to V;prefer+to V+than+V