货物线容车数按什么计算？
参考答案：
按其有效长与换算长度11m或14.3m的比值计算。
患者的脉搏短绌见于（）
A.心房颤动
B.心室纤颤
C.频发室性早搏
D.休克
E.室上性心动过速
John _____ knowledge of radio just by staying around the radio station. [ ]
A. caught on
B. worked up
C. took up
D. picked up
