By the use of group action and normal covering we give an answer in some conditions from topological rigidity theorem in this article.

本文通过群作用和正则覆盖，利用拓扑刚性定理对此问题给出一个判定性条件。

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If you have a normal thickness of bone, which is about 0.6 or 0.7 millimeter covering the superior canal, that's very unlikely to ever erode.

如果你有正常厚度——大概0.6 ~ 0.7毫米——的骨头覆盖上半规管，那就很难发生病变了。

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Normal style: exposure suit is designed with a sharp-angled or ring neckline, collocated with gallus trousers or apron, with free breath holes covering back and oxter; or dust coat.

领口采用尖角或环型设计，下装配有背带裤或围裙设计，背片和腋下开创覆盖式透气孔设计，亦有大褂风衣设计，总之可以根据客户需要进行设计和研制。

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If the Spanish political elite - both main parties were implicated in the mismanagement of the cajas - thinks it can get away with things as normal, covering up the shocking collapse of a bank built on political patronage, then the Germans intend the Greek example to be a salutary lesson.

BBC: Will Europe let the Greek political centre fall?