在操作风险管理中通常会对风险动因、风险指标、（）和绩效测评等进行测量和监测。
A.因果模型
B.资本模型
C.历史损失
D.以上都对
参考答案：D
Tom with his friends ______ volleyball since three o’clock.
A．has been playing
B．is playing
C．have been playing
D．have played
