如果企业将客户保持率提高5％，客户的平均价值就会大幅度提高。
参考答案：对
Festivals and celebrations of all kinds _________everywhere since ancient times. [ ]
A. have held
B. were held
C. had been held
D. have been held
对第八对脑神经有损坏，可引起耳聋的是
A．氯霉素B．头孢噻肟钠C．克拉霉素D．克拉维酸钾E．阿米卡星
