【判断题】Planar mechanisms utilizing only lower pairs are called planar linkages.
【单选题】Which molecule is planar?
【判断题】墙体拉伸可以不先不考虑窗洞的问题,在体块墙体拉伸完毕之后,再在墙面 上开窗洞。
【单选题】If all points in a linkage move in parallel planes the system undergoes planar motion and the linkage may be described as a .