从方框中选择最佳选项完成对话

a. Maybe light bulbs(灯泡) are the most useful inventions.

b. What kind of books do you want to borrow?

c. Great inventions have changed the world a lot.

d. Why do you think so?

e. What do you think the most useful invention is?

A: Where are you going, Tony?

B: The library. I want to borrow some books.

A:

B: About inventions. You know I have to prepare for the science lesson.

A: And we humans are really great.

B: That's true. People have made lots of inventions.

A:

B: Sorry, I'm not sure.

A: I don't agree. In my opinion, cars are the most useful.

B:  

A: Because I can go anywhere quickly and conveniently in my car.