阅读下面一段对话，根据对话内容，从方框中选择恰当的句子将对话补充完整（选项中有两项是多余的）。(提示：每个选项只用一次，选项中有一项为多余选项)

A：Let's talk about the future. It always makes us excited.

B：OK. 

A：I think every home will have a car.

B：

A：I disagree with you. Cars in the future will be green ones.

B： Do you think people will have more free time in the future? 

A：Yes. That's because there will be more robots. They'll help people do most of the work.

B：I think so.

A：No, I think more people will live in the countryside in the future.

B：

A：Because the air in the countryside is very clean. It's good for people's health.

B：You are right.

A. Sounds great. B. What's your prediction about the future? C. There will be fewer people on the earth. D. Why do you think so? E. But I think more cars will bring more pollution. F. Do you think there will be more people living in the city?