1. Although she eats lots of food, she is still very slim.
=> In spite of eating lots of food, she is still very slim.
2. We will be using biogas for cooking and heating at this time next month.
=> Biogas will be used for cooking and heating at this time next month.
3. A group of foreigners visited the slums last week, didn’t they? (VISIT)
Did a group of foreigners visit the slums last week?
4. The countryside doesn’t suffer as much pollution as the city. (LESS)
 The countryside suffers less pollution than the city.

although she eats lots of food, she is still very slim. -> in spite of ________eating lots of food , she is still very slim_________

 a group of foreigners visited the slums last week, didn't they ? (VISIT). -> _______Did a group of foreigners visit the slums last week?__________
the countryside doesn't suffer as muh pollution as the city. (LESS) -> _______The city doesn't suffer as less pollution as the countryside____