熔剂性烧结矿主要矿相是钙铁橄榄石和极少量的硅酸钙、硅酸二钙及玻璃质等。（）
参考答案：对
The weather that day may not be as good as expected, in ________ case we will have to put off the
event.[ ]
A. what
B. that
C. this
D. which
在实际生产中常采用（）来调节离心泵的流量。
A、改变进口阀开度
B、改变出口阀开度
C、改变泵的转速
D、旁路回流
