下列哪种结构没有参与会阴境界的围成（）
A.耻骨下支
B.尾骨尖
C.耻骨联合下缘
D.坐骨棘
E.骶结节韧带
参考答案：D
Little Tom was very nervous in front of so many strangers, so he ____ and ran to his mother. [ ]
A. turned out
B. turned off
C. turned down
D. turned around
当被测压力较稳定，弹性式压力表在选择压力表量程时，最大压力值应不超过满量程的（）。
A、3/4
B、2/3
C、1/3
D、1/2
