`6` You should switch off electricaal appliances when they aren't in use

`=>` It's a good idea to do sth : nó là 1 ý tưởng tốt để làm gì

`=>` should + V nguyên : nên làm gì

`=>` Đưa ra lời khuyên 

`7` Despite the most polluting of fossil fuels coal , it is still the largest sources of energy worldwide

Hoặc : Despite the fact that coal is the most polluting of fossil fuels , it is still the largest sources of energy worldwide

`=>` Despite/In spite of + danh từ/cụm danh từ/V-ing , S + V + O 

`=>` Although + S + V + O , S + V + O 

`8` People wil use biogas for fuel in homes and for transport

`=>` Câu chủ động thì TLĐ : S + will + V nguyên + O 

`=>` Câu bị động thì TLĐ : S + will + be + Ved/V3 + (by O) 

6, You should switch off electrical appliances when you aren't in use.

7, Despite being the most polluting of fossil fuels, coal is still the largest sources of energy worldwide.

8, People will use biogas for fuel in homes and for transport.

Nếu có chỗ nào chưa hiểu bạn nhắn lại cho mình nhé, mình sẽ giải thích lại cho.

Chúc bạn học tốt^^