移频键控
参考答案：瞬时载波频率取决于输入值，如果码元边界的相位连续，就会产生连续相位移频键控（CPFSK）。
—How did you go home after the party last night？
—Well，there were no buses we had to walk.
A．so as to
B．in order to
C．so that
D．in order that
排污单位都应当根据当地环保部门的缴费通知单，在（）向指定银行缴付排污费
A、10天内
B、15天内
C、20天内
D、25天内
