Here are the comparative forms with "than" added where necessary:

1. Average incomes in rural areas are **slower than** those in the city.
2. The conditions they're living in are **worse than** we thought.
3. Your book looks **more interesting than** mine. Can I borrow it for some days?
4. The evening in the countryside is often **more peaceful than** that in the city.
5. Many families in the suburbs are **happier than** the ones you meet in the urban.
6. With the help of technology we can live **more conveniently than** ever before.
7. Watching football is one of Britain's top leisure activities, even **more popular than** eating out.
8. Henderson said that he could run **faster than** anybody else in the class.
9. This year's harvest season seems to come **earlier than** usual.
10. All these students are good, but some work **harder than** others.