听力原文：

Environment Problems

The environment has been getting worse and worse for many years. Factories and transportation are the main causes of pollution. Smoke from factory chimneys and fumes from cars pollute the air. Many people in towns and cities are throwing away all kinds of litter into the water. Wastewater from factories is poured into rivers and this causes water pollution. Machines in the factories and engines of all the vehicles make noises. People throw their garbage everywhere. We can find metal tins, wooden chopsticks and all kinds of packages in public places. To provide customers with convenience, some producers and shops use plastic packaging materials, which can be thrown away immediately after use. Most of the packaging materials can be thrown away, leading to “white pollution”.

参考答案：

1. Smoke 2. litter 3. engines 4. everywhere 5. white