They found that on tannin-rich oak leaves, the virus is considerably less effective at killing caterpillars than when it is on aspen leaves, which are lower in phenols.

他们发现，在富含单宁酸的橡树叶上，病毒杀死毛虫的效果要比在白杨树叶子上的效果差得多，因为白杨树叶子的酚含量较低。

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Oak leaves turn brown but stay on the trees.

橡树的叶子变成棕黄色，但仍然留在树上。

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Gently, he laid it down on the bed of brown oak leaves.

他轻轻地把它放在橡树叶上。

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You can use mulch made from bark, pine needles,cottonseed or oak leaves.

VOA: special.2010.06.15

The caterpillars strip oak trees of their leaves but are also toxic to people.

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