题目

已知双曲线=1(a>0，b>0)的右焦点为F，右准线与一条渐近线交于点A，△OAF的面积为(O为原点)，则两条渐近线的夹角为  (    )   A．30°    B．45°    C．60°    D．90° 答案：DWith the world changing fast, we have something new ________(deal) with all by ourselves every day.