VMI系统最主要可分成两个模块，一个是需求计划模块，可产生准确的需求预测；第二个是生产计划模块。
参考答案：错
It is recommended that the project ________ until all the preparations have been made.
A．is not started
B．will not be started
C．not be started
D．is not to be started
利用VOR进行定位，要求至少同时接收到（）VOR的信号。
A.1个
B.2个
C.3个
D.4个
