变速箱之倒档齿轮用于()
A.改变转速比
B.改变传动方向与减速比
C.改变齿轮传动方向
D.改变扭力比
参考答案:C
使尿比密降低的因素是()
A.混有X射线造影剂
B.温度降低
C.温度升高
D.蛋白尿
E.含有葡萄糖
Her panic was transient, and ceased when she began to speak.()
A. beyond description
B. unnoticed
C. passing quickly
D. vague