浮鞋的内部（包括锥型段部分）通常由水泥或热塑性材料组成，如果在套管鞋处井眼还需要继续加深的话这种材料必须被钻掉。
The inside (including the taper) is usually made of cement or thermoplastic, since this material must be drilled out if the well is to be deepened beyond the casing point.
牙医把她牙齿上蛀坏的部分钻掉。
永久型封隔器由容易钻掉或者磨铣掉的材料制成。
Permanent packers are constructed of materials that are easy to drill or mill out.
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