听力原文：

G: There was a traffic accident here last night.

B: How did the accident happen?

G: The fog was responsible for the accident. The traffic accident led to a chain of events.

B: Anybody hurt in the traffic accident?

G: In total, six people were injured in the traffic accident. A driver was badly hurt. They were sent to hospital after the accident.

B: I think the accident was caused by careless driving.

G: The number of road accidents is on the rise. People should drive carefully.

B: In my opinion, most road accidents can be avoided. The best way is to build more overpasses and underpasses in big cities.

Question: What is the best way to avoid road accidents in big cities?

参考答案：

The best way is to build more overpasses and underpasses in big cities.