渐开线直齿圆柱齿轮的正确啮合条件两轮模数和()相等.
参考答案:压力角
The store had no more red shoes _____, so Mary chose brown ones instead.
A.in demand
B.in store
C.in need
D.in stock
煤矿企业应按照国家法律、法规和卫生行政主管部门的规定对哪些人员进行职业健康检查?