模拟信号数字化的基本原理。
参考答案：
抽样，量化，编码。
急性肺水肿时两肺可闻及
A．水泡声B．干啰音C．湿啰音D．心包摩擦音E．哮鸣音
We have read for an hour. Now let's stop ____a rest. [ ]
A. had
B. have
C. to have
D. having
or an hour. Now let's stop ____a rest. [ ]