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Network equipment supporting the use of flow control mechanisms has been recently installed. What is the purpose of flow control in a data network?（）
A. It ensures that data is retransmitted if an acknowledgment is not received.
B. It reassembles segments in the correct order on the destination device.
C. It provides a mechanism for the receiver to control the transmission speed.
D. It regulates the size of each datagram segment.
E. All of the above are functions of flow control
船舶在正常状态下，港口航行时，必须两台发电机并联运行。
A. 正确
B. 错误
氧气管道内氧气流速，按我国氧气站设计规范规定允许压力为（）；氧气流速为（）。
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