Trees are natural air conditioners. They take harmful gas from the air, and release oxygen into the air.

树木是天然的空气净化器，他们可以吸收空气中有害的气体并向空气中释放氧气。

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Trees are natural air conditioners. They take harmful gas from the air, and release oxygen into the air.

树木是天然的空气净化器，他们可以吸收空气中有害的气体并向空气中释放氧气。

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