First thing you want to do is drill a pilot hole in the right location.
第一件事，你想要做的就是钻一个先导孔在正确的位置。
Application of inverse well drill will permit quick and safe excavation of pilot shaft.
应用反井钻机开挖导井可达到快速安全的效果。
Application of inverse well drill will permit quick and safe excavation of pilot shaft.
应用反井钻机开挖导井可达到快速安全的效果。
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