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问题 推断题

A、B、C、D是中学化学常见的有机物，它们之间有如下转化关系（部分产物已略去）。其中A俗称醋酸，C是一种有香味的油状液体。

请填写下列空白：

(1)A、B、C的结构简式：A为____；B为____；C为____。

(2)反应①所属的反应类型为___；反应②的化学方程式为____。

(3)B与金属钠反应的化学方程式为____。

答案

(1)CH3COOH ；CH3CH2OH； CH3COOCH2CH3

(2)酯化反应（或取代反应）； 2CH3CH2OH + O2 2CH3CHO+2H2O

(3)2CH3CH2OH+2Na 2CH3CH2ONa+H2↑

单项选择题

The primary advantages of a Client/Server system arise from splitting the processing between the client system and the database server. Since the bulk of the database processing is done on the back-end, the speed of the DBMS isn’t tied to the speed of the (31) .
The major disadvantage of Client/Server system is the increased cost of (32) and support personnel who maintain the database server. There is also the issue of (33) with so many parts comprising the entire C/S system; Murphy’s Law can kick in-the more pieces that compose the system, the more pieces that can fail. It’s also harder to track down problems when the system (34) . And it can initially take longer to get all the components set up and working together. All this is compounded by the general lack of experience and expertise of potential support personnel and programmers, due to the relative newness of the technology. As C/S system become more common, this problem should abate.
Therefore the C/S system is more (35) .

A．complexity

B．possibility

C．simplicity

D．variety
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单项选择题

属于麻醉镇痛药的是（）

A．盐酸氯胺酮

B．恩氟烷

C．盐酸麻黄碱

D．盐酸普鲁卡因

E．盐酸吗啡
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