拉伸屈服应力是在拉伸应力—应变曲线上()处的应力.
A、中点
B、断裂
C、屈服点
D、零点
参考答案:C
Lucy _____ born _____ London _____ May 1, 1986 [ ]
A. is; in; on
B. was; in; on
C. was; in; in
D. is; at; on
门机司机如何做到按指挥信号操作?