农民工目前已成为国有施工企业的主力军，农民工素质的高低直接影_爱下问搜题

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问题单项选择题

农民工目前已成为国有施工企业的主力军，农民工素质的高低直接影响工程质量的优劣。2011年2月，据人力资源和社会保障部统计，我国农民工人数已达( )。

A．2.42亿

B．9000万

C．1.34亿

D．6700万

答案

参考答案：A

解析：到“十一五”末，我国农民工总数达2.42亿人。农民工在为我国现代化建设作出巨大贡献的同时，其就业、社会保障、教育培训等权益保障也取得长足进展。故选A。

解答题

已知离心率为

的椭圆C₁的顶点A₁，A₂恰好是双曲线

-y2=1的左右焦点，点P是椭圆上不同于A₁，A₂的任意一点，设直线PA₁，PA₂的斜率分别为k₁，k₂．
（Ⅰ）求椭圆C₁的标准方程；
（Ⅱ）试判断k₁•k₂的值是否与点P的位置有关，并证明你的结论；
（Ⅲ）当k1=

时，圆C₂：x²+y²-2mx=0被直线PA₂截得弦长为

，求实数m的值．
设计意图：考察直线上两点的斜率公式、直线与圆相交、垂径定理、双曲线与椭圆的几何性质等知识，考察学生用待定系数法求椭圆方程等解析几何的基本思想与运算能力、探究能力和推理能力．第（Ⅱ）改编自人教社选修2-1教材P39例3．

完形填空

When I was a small child, during the war, we were very poor and we lived in a faraway village. One day, on the road, I found the __36__ pieces of a mirror. There was a German motorcycle accident.
I tried to find all the pieces and put them __37__, but it was not possible, so I kept only the __38__ piece and I made it round. I began to __39__ with it as a toy and became greatly attracted by the __40__ that I could reflect（反射）light to dark places where the sun would never shine in __41___holes and some other dark places. It became a __42__ for me to get light into the darkest places I could find.
I __43__ the little mirror, and, as I ___44__ up, I would take it out when I had nothing to do and __45__ the game. As I became a __46__, I grew to understand that this was not __47__a child’s game but a metaphor（象征）for what I might do with my life. I came to __48___ that I am not the light or the source（来源）of light, but light—truth, understanding, knowledge—is __49___, and it will shine in many dark places only if I reflect it.
I am just a single piece of a mirror whose ___50__ design and shape I do not know. __51___, with what I have I can reflect light into the dark places of this __52__， into the black places in the___53__ of men—and change some things __54___ some people. Perhaps others may see and do the same. This is what I am about. This is the __55___ of my life. （269 words）

D．grandfather