在结构上采用了三翼四齿的钻头体、弧槽形排粉沟槽，适用于硬、中硬、软岩的三种齿形。
The drill bit body has three wings four cylindrical tungsten carbide inserts and curved slots for removal of cuttings.
鲨鱼的种类有很多，而经常被载攻击人的只有四种 – 牛鲨（学名白真鲨）、虎鲨（学名居氏鼬鲨）、大白鲨（学名噬人鲨）、白鳍鲨（学名灰三齿鲨）
While there are numerous types of sharks, only four are most frequently cited in encounters with humans—the bull shark, the tiger shark, the great white shark and the oceanic white tip shark.
奥古斯塔纳大学（Augustana College）的威廉·汉莫（William Hammer）发现了这种新的生物——一头四到五英尺的鸟臀目恐龙，他认为它与法布尔龙或畸齿龙有血缘关系。
William Hammer of Augustana College found the new creature -- a four- to five-foot ornithischian or bird-hipped dinosaur that he believes is related to the fabrosaur or heterodontosaur.
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