使不等式成立的一个必要不充分条件是（    ）

    A.     B．   C． D． ，或

在等比数列的值为（    ）                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                

    A.9           B．1  C．2    D．3

以双曲线的中心为顶点，右焦点为焦点的抛物线方程是（    ）

  A.      B．     C．    D．

现将10个参加2009年全国高中数学竞赛的名额分配给某区四个不同学校，要求一个学校1名，一个学校2名，一个学校3名，一个学校4名，，则不同分配方案种数共有 （    ）

A.43200               B．12600              C．24          D．20

定义运算：，将函数的图象向左平移（）个单位，所得图象对应的函数为偶函数，则的最小值为（    ）

A.             B．            C．            D．

在空间给出下列四个命题：

①如果平面内的一条直线垂直于平面内的任意一条直线，则⊥；

②如果直线与平面内的一条直线平行，则∥；

③如果直线与平面内的两条直线都垂直，则⊥；

④如果平面内的两条直线都平行于平面，则∥．其中正确的个数是

Ａ．　　　　　    Ｂ．　　　　　  Ｃ．　　　　     Ｄ．

用数1、2、3、4、5可以组成没有重复数字，并且比20000大的五位偶数共有（    ）

A.48个      B．36个         C．24个           D．18个

已知，直线与直线互相垂直，则的最小值等于（    ）

A．1    B．2    C．    D．

已知、是椭圆长轴的两个端点，是它短轴的一个端点，如果与的夹角不小于，则该椭圆的离心率的取值范围是（    ）

A．    B．    C．     D．

已知是定义在上的增函数，函数的图像关于点对称，若对于任意的，不等式恒成立，则当时，的取值范围是（    ）

A．（3，7）    B．（9，25）    C．（13，49）    D．（9，49）