什么是风险，如何度量？
参考答案：
风险是指各种可能结果偏离预期结果的程度。
We were told that Mr Green _____ the office for a few minutes when we arrived.
A．has been away from
B．had left
C．had been away from
D．has left
厘订保险费率的原则是（）。
A.保证补偿
B.公平合理
C.相对稳定
D.促进防损
