城市污水处理场的底泥含有大量的微生物，其中包括一些病原菌，如果不加处理会给环境造成再次污染。

The sludge from city sewage plant contains enormous microorganism, some of them are pathogenic bacteria, which will cause secondary pollution if notsuitably treated.

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现在有人担心，计划修建的穿越湖底的输油管道可能会重新造成污染，导致鱼类数量再次下降。

Fears are now being voiced that the planned construction of an oil pipeline across the lake's bottom might revive pollution and cause the fish population to decline again.

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该法案将在3个月内再次提交参议院审核，法案计划在2011年7月在澳大利亚引入碳污染减少计划。

The bill, which would have led to the introduction of a Carbon Pollution Reduction Scheme in July 2011, will return to the senate in three months.

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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