ag的铜丝灼烧变黑，立即放入下列的某种物质中发生反应，铜丝变红且反应后质量仍为a

将控件添加到工具箱中，应先在工具箱的空白处单击右键，在弹出的快捷菜单中选择______选项，然后在弹出的对框中选择所需的控件。

Which of the following statements about securities exchanges is TRUE（）

A. Continuous markets are markets where trades occur 24 hours per day.

B. Call markets are markets in which the stock is only traded at specific times.

C. Setting a negotiated price to clear the market is a method that is never used in major continuous markets.

符合急性心肌梗死临床特征的是（）

A.多发生在活动后

B.含服硝酸甘油可缓解症状

C.血管痉挛不会导致心肌梗死

D.冠脉内粥样斑块增大、破溃、出血，形成血栓、栓塞使管腔完全闭塞

E.4周后成为陈旧性心肌梗死

Jack  is  watching  NBA  now.  It  is______. of him to slip out of the classroom to watch the NBA

finals during the final season.   [ ]

A. normal            

B. ordinary  

C. common          

D. typical

什么是“黑色幽默”？黑色幽默小说家经常运用哪些艺术手法？