牙形石的自然集群 名词解释

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A . ['正中https://assets.asklib.com/psource/2015113015522399696.jpg 平衡B . 前伸https://assets.asklib.com/psource/2015113015522399696.jpg 平衡C . 侧方https://assets.asklib.com/psource/2015113015522399696.jpg 平衡D . 尖牙保护https://assets.asklib.com/psource/2015113015522399696.jpg E . 完善的接触https://assets.asklib.com/psource/2015113015522399696.jpg 平衡

A . ['正中https://assets.asklib.com/psource/201511261518011720.jpg 平衡B . 前伸https://assets.asklib.com/psource/201511261518011720.jpg 平衡C . 侧方https://assets.asklib.com/psource/201511261518011720.jpg 平衡D . 尖牙保护https://assets.asklib.com/psource/201511261518011720.jpg E . 完善的接触https://assets.asklib.com/psource/201511261518011720.jpg 平衡

A . A、球墨铸铁 B . B、灰铸铁 C . C、白口铸铁 D . D、可锻铸铁

A . A、呈握拳状 B . B、腕背伸30度 C . C、腕稍向尺侧偏斜10度 D . D、拇指绝不能外展 E . E、以上均是

A．N8000集群文件系统VxVM属于非日志文件系统，可支持2T以上的文件 B．文件系统快照采用copy-on-write（写时拷贝技术），和其他的文件集一起共用分区或者卷的存储空间 C．N8000提供的快照是基于文件系统级别的 D．文件系统快照、镜像、复制等特性实现基于存储检查点

It is fairly common for an industrial cluster to break up and for production to move to locations with lower wages when the technology of the industry is no longer rapidly improving--when it is no longer essential to have the absolutely most modern machinery， when the need for highly skilled workers has declined， and when being at the cutting edge of innovation conveys only a small advantage. Explain this tendency of industrial clusters to break up in terms of the theory of external economies.