若一离散无记忆信源的信源熵H（X）等于2.5，对信源进行等长的无失真二进制编码，则编码长度至少为（）。
参考答案：3
You must do your homework now; you ________ computer games all the evening.
You must do your homework now; you
computer games all the evening.
A．have been playing
B．are playing
C．play
D．played
文件名中不能包含空格。
