患儿，男，10岁，自幼发现心脏杂音，易患感冒。查体无发绀，胸骨左缘第3、4肋间收缩期粗糙的吹风样杂音及震颤

室间隔修补术的常见术后并发症是（）

A.传导阻滞

B.喉返神经损伤

C.主动脉关闭不全

D.肺动脉关闭不全

E.瓣周漏

F.残余分流

G.术后高血压

H.二尖瓣关闭不全

An analog signal’s characteristic quantity representing data may 66) . at any instant, any value within a continuous (67) . For example, an analog signal may follow continuously the values of another physical quantity representing data.

A discrete signal is composed of (68) elements in time, each element having one or more characteristic quantities which can represent data. Examples of characteristic quantities are amplitude, waveform, (69) , and position in time. A digital signal is a special case of discrete signals, in which data are represented by a (70) number of well-defined discrete values that one of its characteristic quantities may take in time.

（67）处填（）。

A．interval

B．region

C．range

D．compartment