They think such food may not be clean enough.

他们认为这样的食物可能不够干净。

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Since there have been complaints about the quality of the water in the river, residents must be avoiding the river because they think that it is not clean enough.

由于曾经存在对于这条河水质的投诉，居民一定是因为他们认为河水不够干净才不在这里活动。

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The workers of this nature reserve try to clean it by themselves but their efforts are not enough.

该自然保护区的工人们试图靠他们自己来清理，但他们的努力远远不够。

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But it did say that the engine is 10 percent lighter than a 2.2-liter diesel engine currently sold in markets outside the U.S. and that it runs clean enough not to require complicated exhaust treatments to meet emissions regulations.

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However, in many parts of the world, water is not always clean enough for safe human use, or for sustaining healthy ecosystems.

UNESCO: MEDIA SERVICES

For one, clean energy investments have not had enough time to mature.

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