重吊作业时应操纵起货机使吊起货物()。
A.越高越好
B.视情况而定
C.越低越好
D.能吊出舷外,但不宜过高
参考答案:D
计算经济效益净现值采用的折现率应是:()
A.企业设定的折现率
B.国债平均利率
C.社会折现率
D.银行贷款利率
Sam ()some knowledge of the computer just by watching others working on it.
A. brought up
B. looked up
C. picked up
D. set up