N-CDMA系统采用以下哪种语音编码方式()。
A.PCM
B.QCELP
C.VSELP
D.RPE-LTP
参考答案:A
科研单位为有关单位提供科研服务取得的收入应作为经营收入。()
—You _____ a meal this evening. I had dinner at a restaurant with Tom.
—Well, why didn’t you phone me and let me know?
A.should not cook
B.don’t need to cook
C.needn’t have cooked
D.should have cooked