数据流图是常用的进行软件需求分析的工具,其基本组成包括()。
A. 输入、输出、外部实体和加工
B. 变换、加工、数据流和存储
C. 加工、数据流、数据存储和外部实体
D. 变换、数据存储、加工和数据流
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5英寸软盘的存储容量和每个扇区存储的固定数据是()。
A. 1.44MB,512B
B. 1MB,1024B
C. 2MB,256B
D. 1.44MB,512KB
Complacency towards ecological balance ("It can't happen here!") has resulted in a number of ______.
A. damages
B. wastes
C. catastrophes
D. dangers
The obstacles Nancy Kerrigan faced as she strove (to win) the Olympic ice skating medal at Likehamma in 1944 form (the kind of) story (about whom) a fascinating novel (might) be written.
A. to win
B. the kind of
C. about whom
D. might
考虑下述文法,S为开始符号 G1[S]:S→A A→aAb | ab G2[S] S→AA→aA |a| 下列结论中为真的是()。
A. G1是LR(0)文法,G2不是LR(1)文法
B. G2是LR(0)文法,G1不是LR(1)文法
C. G2是LR(1)文法,G1不是LR(1)文法
D. G1和G2都是LR(1)文法