单选题设复数z满足，则|1+z|=()．

单选题 For most of us, work is the central, dominating fact of life. We spend more than half our conscious hours at work, preparing for work, traveling to and from work. What we do there largely determines our standard of living and to a considerable extent the status we are accorded by our fellow citizens as well. It is sometimes said that because leisure has become more important the indignities and injustices of work can be pushed into a comer, that because most work is pretty intolerable, the people who do it should compensate for its boredom, frustration and humiliations by concentrating their hopes on the other parts of their lives. I reject that as a counsel of despair. For the foreseeable future the material and psychological rewards which work can provide, and the conditions in which work is done, will continue to play a vital part in determining the satisfaction that life can offer. Yet only a small minority can control the pace at which they work or the conditions in which their work is done; only for a small minority does work offer scope for creativity, imagination, or initiative. Inequality at work and in work is still one of the cruelest and most glaring forms of inequality in our society. We cannot hope to solve the more obvious problems of industrial life, many of which arise directly or indirectly from the frustrations created by inequality at work, unless we tackle it head-on. Still less can we hope to create a decent and humane society. The most glaring inequality is that between managers and the rest. For most managers, work is an opportunity and a challenge. Their jobs engage their interest and allow them to develop their abilities. They are constantly learning; they are able to exercise responsibility; they have a considerable degree of control over their own and others' working lives. Most important of all, they have opportunity to initiate. By contrast, for most manual workers, and for a growing number of white-collar workers, work is a boring, dull, even painful experience. They spend all their working lives in conditions which would be regarded as intolerable--for themselves--by those who take the decisions which let such conditions continue. The majority have little control over their work; it provides them with no opportunity for personal development. Often production is so designed that workers are simply part of the technology. In offices, many jobs are so routine that workers justifiably feel themselves to be mere cogs in the bureaucratic machine. As a direct consequence of their work experience, many workers feel alienated from their work and their firm, whether it is in public or in private ownership.

单选题从5个不同的黑球和2个不同的白球中，任选3个球放入3个不同的盒子中，每盒1球，其中至多有1个白球的不同放法共有______种．

单选题已知F1、F2是椭圆(a＞b＞0)的两焦点，B为椭圆在y轴上的顶点，∠F1BF2=120°，则椭圆的离心率e=()．

单选题设f(x)在x0处可导，g(x)在x0处不连续，则f(x)g(x)在x0处 (A) 必不连续． (B) 可能连续必不可导． (C) 可能可导但导数必不连续． (D) 可能存在任意阶导数．

单选题[2013年1月]已知二次函数f(x)=ax 2 +bx+c，则方程f(x)=0有两个不同实根。 (1)a+c=0； (2)a+b+c=0。

单选题“复数a+bi(a，b∈R)为纯虚数”是“a=0”的( )。 A．充分但非必要条件 B．必要但非充分条件 C．充要条件 D．既非充分又非必要条件

单选题函数的连续区间是()。A．(-∞，-2)∪(2，-1)∪(-1，+∞)B．[3，+∞)C．(-∞，-2)∪(-2，+∞)D．(-∞，-1)∪(-1，+∞)

单选题若点P(0，1)在函数y=x2+ax+a的图象上，则该函数的对称轴方程为______。A．B．C．-1D．1

单选题一个正方形在平面直角坐标系中三个顶点的坐标为(一2，一3)，(一2，1)，(2，1)，则第四个顶点的坐标为( )．

单选题假设甲、乙两国关于拥有洲际导弹数量的关系曲线．y=f(x)和x=g(y)的意义是：当甲国拥有导弹x枚时，乙国至少需储备导弹y=f(x)枚，才有安全感；当乙国拥有导弹y枚时，甲国至少需储备导弹x=g(y)枚，才有安全感．这两条曲线将坐标平面的第一象限分成四个区域Ⅰ，Ⅱ，Ⅲ，Ⅳ，如下图所示．双方均有安全感的区域是______．

单选题设f(x)在x=x0处附近四阶连续可导，且f(x0)=f"(x0)=f'"(x0)=0，f(4)(x0)＜0，则y=f(x)在x=x0处______．