Decentraction of the conn-rod small end holecenter with the excircle center of the conn-rod small end hole blank, which causes the hole wall of one side getting thin with the strength dropping.
连杆小头孔中心与连杆小头孔毛坯外圆中心不同心，使一边孔壁变薄，强度下降。
2
Most astronomers believe that the large concentration of mass at the galaxy's center is a black hole whose gravity is causing the gas to whirl.
大多数天文学家认为，星系中心的大量物质是一个黑洞，它的引力导致气体旋转。
3
Recent findings lend strong support to the theory that a black hole lies at the center of the Milky Way and of many of the 100 billion other galaxies estimated to exist in the universe.