RM80清筛车的设计最大挖掘深度(自轨面向下)是()。
A、800mm
B、1000mm
C、1200mm
D、1400mm
参考答案:A
When was it _____ your parents took you to Hangzhou?
A.before
B.if
C.which
D.that
请作图说明储存成本和运输成本的关系及最佳数量点的确定。