24- dictation

A: There are so many problems in the world today.

B: I know. There's water pollution, air pollution, global warming, unemployment.

A: Yeah, and there's the destruction of the rain forests, traffic problems, housing shortages... It can get depressing if you think about it too much.

B: No kidding. What do you think the biggest issues are?

A: I really think air pollution is the most important issue. If we don't reduce pollution and improve air quality, we'll all have health problems.

B: I agree that air pollution is a big problem. The air in the city has become so dirty.