题目

图所示的四种现象中，属于光的色散的是（ ） 答案：【答案】B【解析】试题分析：广场上的激光束射向四面八方是光在空气中沿直线传播；小桥在水中的“倒影”是平面镜成像是由光的反射形成的；水中的筷子弯折是光的折射现象；阳光穿过三棱镜分解成红、橙、黄、绿、蓝、靛、紫七种色光，这就是光的色散，色散也是光的折射现象，故选B。Throughout this long, tense election, everyone has focused on the presidential candidates and how they’ll change America. Rightly so. But selfishly, I’m more fascinated by Michelle Obama and what she might be able to do, not just for this country, but for me as an African-American woman. As the potential First Lady, she would have the world’s attention. And that means that for the first time people will have a chance to get up close and personal with the type of African woman they so rarely see.        Usually, the lives of black women go largely unexamined. The widespread theory seems to be that we’re all hot-tempered single mothers who can’t keep a man. Even in the world of make-believe, black women still can’t escape the stereotype (模式化的形象) of being eye-rolling, oversexed females raised by our never-married, alcoholic mothers.        These images have helped define the way all black women are viewed, including Michelle Obama. Before she ever gets the chance to commit to a cause, charity or foundation as First Lady, her most urgent and perhaps most complicated duty may be simply to be herself.        It won’t be easy. Because few mainstream publications (出版物) have done in-depth features on regular African-American women, little is known about who we are, what we think and what we face on a regular basis. For better or worse, Michelle will represent us all.        Just as she will have her critics, she will have millions of fans who usually have little interest in the First Lady. Many African-American blogs have written about what they’d like to see Michelle bring to the White House — mainly showing the world that a black woman can support her man and raise a strong black family. Michelle will have to work to please everyone — an impossible task. But for many African-American women like me, just a little of her poise (沉着), confidence and intelligence will go a long way in changing an image that’s been around far too long. 48.   Why does Michelle Obama hold a strong fascination for the author? A. She serves as a role model for African-American women. B. She possesses many admirable qualities becoming a First Lady. C. She will present to the world a new image of African-American women. D. She will pay close attention to the interests of African-American women. 49.   What is the common stereotype of African-American women according to the author? A. They are victims of family violence.                 B. They are of an inferior social group. C. They use quite a lot of body language.                     D. They live on charity and social welfare. 50.   What do many African-Americans write about in their blogs? A. Whether Michelle can live up to the high expectations of her fans. B. How Michelle should behave as public figure. C. How proud they are to have a black woman in the White House. D. What Michelle should do as wife and mother in the White House. 51.   What does the author say about Michelle Obama as a First Lady? A. However many fans she has, she should remain modest. B. She shouldn’t disappoint the African-American community. C. However hard she tries, she can’t expect to please everybody. D. She will concern herself with African-American women’s welfare.