由题意得;乙数是:(a-b)÷4.
故选:C.
John's success has nothing to do with good luck. It is years of hard work _____ has made him what he is today. [ ]
A. why
B. when
C. which
D. that
源程序的文档化不包括( )。
A.符号名的命名要有实际意义
B.正确的文档形式
C.良好的视觉组织
D.正确的程序注释