世界上最优质的托帕石主要来源于（）
A.中国
B.美国
C.巴西
参考答案：C
It was several years I finally realized David had lied to me.
A．when;that
B．that;when
C．before;that
D．until;why
远期利率协议是指按照约定的实际本金，交易双方在约定的未来日期交换支付浮动利率和固定利率的远期协议。( )
