词典释义：
break or fall apart into small fragments, especially over a period of time as part of a process of deterioration
破碎，碎裂
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the plaster started to crumble 灰泥开始碎裂了
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[as adj.
crumbling ]their crumbling ancestral home 他们家摇摇欲坠的祖屋。
[with obj.]cause (something) to break apart into small fragments
使破碎，使碎裂
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the easiest way to crumble blue cheese 把蓝奶酪弄碎的最简单的方法。
(of an organization, relationship, or structure)disintegrate gradually over a period of time
（组织，关系，结构）瓦解，崩溃
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the party's fragile unity began to crumble .该党脆弱的统一开始瓦解了。
〈英〉 （经烹调用作水果浇头的）脂质面包屑。
[mass noun]a pudding made with such a topping and a particular fruit
面包屑水果布丁
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apple crumble 面包屑苹果布丁。
"late Middle English： probably from an Old English word related to
