David bought the most expensive car than we did.
=> David bought a more expensive car than we did.
6. Because of tired, we could not go to school yesterday.
=> Because we were tired, we could not go to school yesterday.
7. Why are these two schools so different with each other.
=> Why are these two schools so different from each other?
8. Because of the traffic was heavy, we were late for work.
=> Because of the heavy traffic, we arrived late for work.
9. The doctor advised us doing exercise every morning.
=> Doctors advised us to do exercise every morning.
10. It is very kind of her to help me a lot with my homework.
=> She was very kind to help me a lot with my homework.
Dễ vãi!