Skeptics argue,however, that rising temperatures and warmer oceans are part of a natural cycle and are not convinced the changes are a result of man's pollution.

VOA: standard.2009.05.03

But again, the more people cycle, the less pollution we have.

但是再次地，人们骑自行车越多，污染就会越少。

我使用自行车 - SpeakingMax英语口语达人

But again, the more people cycle, the less pollution we have.

但是再次地，人们骑自行车越多，污染就会越少。

我使用自行车 - SpeakingMax英语口语达人