下列不属于隔风设施的是（）A.临时风门 B.临时密闭 C.风硐 D.永久风墙

He spoke in such a low voice that it was impossible to make out exactly ___ he was trying to say. [ ]

A. it was what that

B. what was it that

C. that what it was

D. what it was that

4种催化机理：临近+定向效应、工价催化、广义酸碱催化、（）

下列各选项中的三种固体通过分别加水就能加以鉴别的是（　　）

A．氯化钠、硝酸铵、氢氧化钠

B．氯化钠、硫酸钠、硫酸钡

C．氢氧化钠、氢氧化钾、氢氧化钡

D．氯化钠、硫酸钡、无水硫酸铜

根据企业客户档案的分类管理原则，企业客户可以根据交易数量利市场地位划分为老客户、新客户利未来客户。