Daming: What do you think, Betty? Which of these inventions is the most important?

Betty: It’s difficult to say. They’ve all changed people’s lives.

Lingling: I love my mobile phone because I can use it anywhere. It’s so useful.

Daming: Yes, all my friends’ numbers are kept in my phone, so I don’t need a notebook.

Betty: Today’s cameras are better than old cameras because they don’t need film.

Daming: Yes, and the photos can be sent by email.

Lingling: Well, I think everything was changed by computers to some degree, so I think the computer is the most important invention.

Daming: I agree. I can’t imagine living without one.