仓库收发货差错率一般应控制在______。
A．0.1%以下 B．0.3%以下 C．0.5%以下 D．0.7%以下
参考答案：C
I'm glad to see my pet dog well _____care of when I was away. [ ]
A. take
B. to be taken
C. taken
D. taking
图示连续梁，EI=常数，欲使支承B处梁截面的转角为零，比值a/b应为：（）
A.1／2
B.2
C.1／4
D.4
