第1题：
A.A
B.B
C.C
D.D
第2题：
What was the purpose of Goldman’s invention? (No more than 10 words)
It was to make shopping easier and attract more business.
第3题：
The purpose of two questions in the second paragraph is to ________.
[A] demonstrate why people are amused
[B] display what people laugh at
[C] bring to light the phenomenon of laughter
[D] accent what a phenomenon laughter really is
第4题：
what is the purpose of classification？
第5题：
what is the purpose of frame-relay LMI？
第6题：
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
第7题：
For the purpose of training and drills，if reasonable and practicable，rescue boats on board must be launched with their assigned crew ______．
A.once a week
B.once a month
C.once a year
D.twice a year
第8题：
what is the use of a purifier ?explain the purpose of a gravity disc ?
第9题：
What is the purpose of an administrative distance？
第10题：
Network equipment supporting the use of flow control mechanisms has been recently installed. What is the purpose of flow control in a data network?（）