1.内角的对边分别为,已知,则(       )
A.                                B.                             C.                               D.
2.的展开式中x4的系数为(     )
A.10                              B.20                              C.40                              D.80
3.直线与圆交于、两点,则(    )
A.                           B.                             C.                             D.
4.函数 y =loga (x -4) +2(a >0 且a ¹1)恒过定点(    ) 
A.(4, 2)                     B.(4,0)                   C.(5,0)                  D.(5,2)
5.双曲线的一个焦点到渐近线的距离为(    )
A.                               B.                               C.2                                D.
6.过抛物线的焦点F作直线l交抛物线C于A,B两点,若点A到抛物线的准线的距离为3,则(    )
A.                               B.3                                C.                               D.4