加压精馏塔，常压精馏塔加量程序正确的是（）。A、先加蒸汽，再加入料最后加回流 B、先

中国近代史既是中国社会沦为半殖民地半封建社会的历史，又是中国追随世界历史发展潮流，走向近代化的历史。结合有关史实，回答下列问题：

（1）结合列强发动的主要侵华战争简要说明中国社会性质的变化历程。

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（2）中国近代化的起步在经济方面有何尝试？结果和影响如何？

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（3）中国近代化的起步在政治方面取得了什么成果？

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（4）在近代，先进的中国人一直在向西方学习，但始终没有使中国富强起来。改革开放后，中国迅速富强起来了，你从中得到了什么启示？

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根据《全民所有制工业企业法》的规定，企业对关键设备、成套设备和重要建筑物，( )

A．可以自主决定出租

B．可以自主决定有偿转让

C．可以自主决定抵押

D．抵押和有偿转让须经政府主管部门的批准

A transport layer protocol usually has several responsibilities. One is to create a process-to-processcommunication UDP uses ______ numbers to accomplish this. Another responsibility is to provide controlmechanisms at the transport level, UDP does this task at a very minimal level. There is no flow control mechanismand there is no ______ for received packet. UDP, however, does provide error control to some extent. If UDPdetects an error in the received packet, it will silently drop it.
The transport layer also provides a connection mechanism for the processes. The ______ must be able to sendstreams of data to the transport layer. It is the responsibility of the transport layer at ______ station to make theconnection with the receiver chop the stream into transportable units, number them, and send them one by one. Itis the responsibility of the transport layer at the receiving end to wait until all the different units belonging to thesame process have arrived, check and pass those that are ______ free, and deliver them to the receiving process asa stream.

A．hop

B．port

C．route

D．packet

在没有世界贸易组织严格界定条件所列的例外情况下，一成员国不得歧视来自其他成员国的产品和提供者；同时，一成员国不得对合法入境的外国产品运用低于本国产品的歧视性待遇，这是“无歧视原则”的含义。 ( )

道岔护轨轮缘槽宽度为42mm，容许误差为－1～+3mm，斥离尖轨非工作边与基本轨工作边的最小距离不小于（）mm。

A.62

B.63

C.66

D.64