按产生挂账的原因不同，可分为（）。
A.正常结算性挂账
B.操作差错挂账
C.客户资金挂账
D.系统挂账
参考答案：A, B, D
0.02扩大到它的（ ）倍是20。
—I was on the point of crossing the road _______ the car accident happened.
—So you are a witness.
A．where
B．when
C．that
D．which
