系统设计工作的重点在于（）。
A.了解当前系统的状况；
B.了解对系统的要求；
C.对数据收集与调研；
D.以上都不是
参考答案：D
请根据句意用所给单词的适当形式填空。
小题1:The teacher devoted his lifetime to (teach) his students.
小题2:While (watch) the programme, the children felt excited.
小题3:When we got to the cinema, the film (begin).
小题4:When I was young, my teacher told me that the earth (go) around the sun.
小题5:Titanic is a romantic film (direct) by James Cameron
关闭多层交换的命令是（）.
A、no iproute
B、no iprouting
C、no swtichport
D、swtichport
