羊水过多经 * * 放水时速度每小时不超过多少毫升（）
A.200
B.300
C.400
D.500
E.700
参考答案：D
跟单员进行原材料采购跟单的中心任务是( )。
A．交货时间合理
B．交货价格合理
C．交货地点合理
D．交货数量合理
He made _____ experiments to prove his theory, and the number _____ added up to 600.
A．a large number of ;have
B．a great deal of; has
C．a great many; has
D．plenty of; have
