An upper guard must cover the entire blade of the saw.
上防护装置必须能够覆盖圆锯的整个刀片。
Upper arm is about equal in length to the shoulder blade in order to allow for good extension.
上臂长度约等于肩胛骨，以便为良好的扩展性。
Upper arm is about equal in length to the shoulder blade in order to allow for good extension.
上臂长度约等于肩胛骨，以便为良好的扩展性。
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