可作为COPD患者长期吸入的药物为（） A.异丙托溴铵 B.沙丁胺醇 C.沐

Today’’s lecture we’’ll center on the prehistoric people of Nevada Desert. Now most of these prehistoric desert people (36)______the countryside throughout the year. You might think that they’’re wandering aimlessly. Far from it, they actually followed the (37)______of carefully planned moves. Where they moved depended on where food was (38)______. Places where plants were ripening or fish were (39)______. Now often when these people moved, they carried all their (40)______on their backs. But if the journey was long, extra food and tools were sometimes stored in caves or (41)______rocks. One of these caves is now an exciting (42)______ site. Beyond its small opening is a huge underground (43)______. Even though the cave is very large. It was certainly too dark and dusty for the travelers to (44)____________. But it was a great place to (45)____________. And tremendous amounts of food supplies and artifacts have been found there.The food includes dried fish, seeds and nuts. The artifacts include stone spear points and (46)____________. The spear points are actually rather small. Here is a picture of some that were found. You can see their size in relation to the hands holding them.

已知甲、乙两种物质的相对分子质量分别为M和N，若将甲、乙两种物质的溶液混合，当溶液中甲与乙的质量比为2M:N时，充分反应后溶液的pH=7，则甲和乙应是下列物质中的[ ]

A．HCl和KOH

B．Na₂CO₃和Ba(OH)₂

C．HCl和Ca(OH)₂

D．NaOH和H₂SO₄

已知：，向IL含有的溶液中通入适量氯气，溶液中各种离子的物质的量变化如下图所示。横、纵坐标的单位均为mol。有关说法不正确的是

A. 线段BC代表Fe³⁺物质的量的变化情况

B. 原混合溶液中C(FeBr₂)= 6 mol/L

C. 当通入Cl₂2mol时，溶液中已发生的反应可表示为：  

D. 原溶液中 

某高中生高考前不看数理化课本，而天天学习《学生守则》，这属于( )。

A．言语异常
B．思维异常
C．情绪反应异常
D．人格异常

脉冲输送的气流速度最大为6m/s，而连续式风送的气流速度最小为（）m/s。

A、8

B、12

C、15

D、20