克拉通包含通常为前寒武纪岩石的结晶基底，即地盾，也包含围绕地盾的并在其上有平卧或近于平卧的沉积物或沉积岩层的地台。

A craton includes a crystalline basement of commonly Precambrian rock called a shield, and a platform in which flat-lying or nearly flat-lying sediments or sedimentary rock surround the shield.

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患者平卧位、俯卧位或坐位。

Patients took supine position, prone or sitting position.

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