Interviewer: David, what do you see as the main problems with the environment?

David: Well, in a nutshell, the most     1     problem of all is the climate. The world's climate seems to be getting warmer.

Interviewer: We've seen a lot of     2     of that, haven't we? Hotter summers, warmer winters, that kind of thing.

David: Yes, we have. Also, scientists have found that the ice at the Poles is beginning to melt.

Interviewer: We've heard that too. Is that really happening?

David: Yes, I'm afraid it is. And at sometime in the future, the ice may melt completely. Then it's possible that the sea could rise and coastal cities like New York and Shanghai could disappear under water.

John: It sounds very     3    .

David: I couldn't agree with you more. It's scary!

Interviewer: Can you explain why the climate's getting warmer?

David: Well, I'll do my best! It's pollution that's the problem. Gases from cars enter the atmosphere and stop the sun's heat from leaving the atmosphere. And factories give out chemicals that do the same thing. So as a result, the climate is getting warmer.

Interviewer: From what I understand, carbon dioxide from cars is a     4     problem.

David: You're absolutely right. Carbon dioxide is the gas that does most     5     to the atmosphere. But we have a problem with trees too. You see, trees give out oxygen and take in carbon dioxide. So they're very useful because they use up the carbon dioxide.