单项选择。
A: What are you doing?
B: We are making cake.[ ]
A. a
B. an
C. the
D. /
答案:A
从所给的四个选项中,选择最合适的一个填入问号处,使之呈现一定的规律性()
A.
B.
C.
D.
A transport layer protocol has several responsibilities, One is to create a process-to-process (program-to-program) communication; TCP uses port (1) to accomplish this. Anotherresponsibility of a transport layer protocol is to create a(2)and error-control mechanism atthe transport level. TCP uses a sliding(3)protocol to achieve flow control. It uses theacknowledgment packet, time-out, and retransmission to achieve (4) control. The transportlayer is also responsible for providing a connection mechanism for the application program. Theapplication program sends (5)of data to the transport layer. It is the responsibility of thetransport layer at the sending station to make a connection with the receiver.
(1)是()
A.numbers
B.connection
C.diagrams
D.resources