关于斜齿轮,正确的是()。
A、螺旋角B常用8°-15°,以使轴向力不过大
B、端面参数是非标准参数
C、啮合时,两轮轮齿的螺旋方向是一致的
D、端面参数是标准参数
参考答案:A
Teenagers would rather_____ secrets with friends than _____ about them with parents.
A.sharing; talk
B.share; talking
C.share; talk
D.sharing; talking
简述LPG的颜色、气味和毒性?