下列各选项中，（）不是物流信息的特征。
A．信息量大
B．物流作业量大
C．动态性强
D．来源多样化
参考答案：B
They had kept working for several weeks everything was in order.
A．before
B．after
C．since
D．unless
如何使用万用表判断二极管极性.
