A．形式简单
B．是由不同符号组合而成
C．可以编码加密
D．信号传递时容易失真
答案：D
—Why has he been so upset?
—He didn’t leave the things _____ they belonged, for _____ he was scolded by his parents.
A．which; that
B．which; this
C．where; whose
D．where; which
在对数据实行等距分组的情况下，组距与组数的关系是( )。
A．无任何关系
B．反比关系
C．正比关系
D．组距总是组数的5倍
