排烟口设置原则是什么？

请用分子、原子的知识，分析并回答下列问题：

（1）体温计中的金属汞，由许许多多的汞______构成；

（2）干冰升华，体积变大，主要是由于二氧化碳分子______变大造成的；

（3）由氯原子结构示意图

可判断出氯原子在化学反应中容易______电子．

His sudden ______ of violent anger put an unpleasant end to the meeting.

A．power

B．attack

C．burst

D．express

—We were surprised to hear that the reason_______ she gave for her absence was______ her mother was ill.

—Yes，we saw her mother was at the supermarket that morning.

A．why；that

B．which；that

C．that；because

D．why；because

某货物FOB价为200美元/t，用影子价格估算的出口费用为50元/t，影子汇率1美元=6.5元人民币，则货物的影子价格(出厂价)为()元/t。

A.1350

B.1625

C.975

D.1250

分层压裂工艺措施的通常采用是（）、投球和限流。

A.卡双封

B.卡封护套

C.油套合注

D.填砂