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问题 单项选择题

醇类成分( )

A．Na2SO3
B．1% HCl或H2SO4
C．GirardT或GirardP
D．丙二酸单酰氯
E．2% NaOH
从挥发油乙醚液中分离得到下列成分，应加入

答案

参考答案：D

解析：[知识点] 挥发油的提取与分离

多项选择题

企业档案管理学的基本研究对象是（）。

A、企业档案

B、企业档案管理

C、企业档案工作
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单项选择题

A transport layer protocol has several responsibilities, One is to create a process-to-process (program-to-program) communication; TCP uses port (11) to accomplish this. Another responsibility of a transport layer protocol is to create a (12) and error-control mechanism at the transport level．TCP uses a sliding (13) protocol to achieve flow control．It uses the acknowledgment packet，time-out，and retransmission to achieve (14) control．The transport layer is also responsible for providing a connection mechanism for the application program．The application program sends (15) of data to the transport layer．It is the responsibility of the transport layer at the sending station to make a connection with the receiver．

A．packet

B．time

C．error

D．phase
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