春天，毛毛虫的出现时间和树木的萌芽一致；鸟儿开始筑巢的时间要跟毛虫出现的时间吻合，用来哺育幼鸟。

In spring, caterpillars time their emergence to coincide with the bud burst of trees; birds start nesting when they can feed those newly emerged caterpillars to their fledglings.

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春天，毛毛虫的出现时间和树木的萌芽一致；鸟儿开始筑巢的时间要跟毛虫出现的时间吻合，用来哺育幼鸟。

In spring, caterpillars time their emergence to coincide with the bud burst of trees; birds start nesting when they can feed those newly emerged caterpillars to their fledglings.

youdao