监护脐带先露或脐带脱垂的手段包括下列哪些项目：A．胎儿监护仪 B．超声多普勒 C．脐

折线统计图能清楚地表示数据的增减变化情况。[      ]

离心式压缩机密封的形式通常采用（）的迷宫密封。

In the following essay, each blank has four choices. Choose the most suitable one from the four choices and write down in the answer sheet.
A socket is basically an end point of a communication link between two applications. Sockets that extend over a network connect two or more applications running on (31) computers attached to the net-work. A socket (32) two addresses: (33) . Sockets provide a (34) communication channel between one or more systems. There are (35) sockets separately using TCP and UDP.

A．message and packet

B．packet and frame

C．stream and datagram

D．flow and block

风硐上的人员进出口应用（）关闭，以防漏风。

粗刮、细刮、精刮在研点数上有何不同？