在研究这些疾病爆发的过程中，科学家们发现受影响的树木会向树叶中释放以酚类物质为主的有毒化学物质进行反击。

In studying these outbreaks, scientists have discovered that affected trees fight back by releasing toxic chemicals, mainly phenols, into their foliage.

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选择以水果和蔬菜为主要配料的主菜，因为它们是膳食纤维、多种维生素和矿物质的理想来源。

Select entrees with fruits and vegetables as key ingredients, as they are a good source of dietary fiber, as well as of many vitamins and minerals.

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奖励坚持精神奖励与物质奖励相结合、以精神奖励为主的原则。

The principle of combining moral encouragement with material reward, taking former as the main form, shall be applied.

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