对照片冲洗质量影响最严重的原因是（）

A.显影液补充量调整偏低

B.定影液混入显影液

C.显影液混入定影液

D.定影液补充量调整偏低

E.冲洗水流量偏低

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