这个市场的主要问题是当地的卫生环境不良。

The main problem in the market is poor health conditions.

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方法选择居住在不同地区的两个观测区居民，无环境不良刺激，无紧张职业。

The inhabitants with no intensive jobs were chosen from two different areas with no harmful stimulation.

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这种疾病的致病原因未明，但是基因和外部环境不良因素的综合影响被认为是其致病的重要原因。

Its cause is unknown, but a complex mixture of genetic and environmental risk factors is thought to be to blame in many cases.

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Similarly,I believe that if we wish to prevent drug abuse in teenagers who grow up in a neighborhood that puts them at risk, the effective prevention is not remedial.

同样，如果我们要防止,青少年受不良的社会环境影响,而滥用药物的情况，但预防的效果不佳。

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