Rachel Carson(1907-1964) was a pioneer of the world’s environmental movement t
hrough her writing about the protection of the natural world. Her 1962 book Silent Spring made her well known by many people. It describes the harmful changes in the environment of using toxic(有害的) chemicals on farmland.
Carson’s career started as a biologist in the US Bureau of Fisheries. In 1951 she published her first book, The Sea Around Us, which became a bestseller. It made her rich enough to leave her job and devote her life to writing. She was a gifted writer. Her next two books were also about the oceans and both topped the book sales lists.
Carson’s book Silent Spring completely change the way America though about nature. It painted a bleak(荒凉的) future for the whole natural world. It led to a nationwide ban(禁止) on the use of a deadly chemical called DDT, and other toxic pesticides(农药) that farmers used for their crops. Many people say the book led to the creation of America’s Environmental Protection Agency.
Since her death, Carson’s name has continued to be connected with protecting the environment. There is now a yearly Rachel Carson Book Prize. Norway awards the Rachel Carson Prize to women who have made great contributions to the field of environmental protection. In 1980, 16 years after her death, she was awarded the Presidential Medal of Freedom, the highest civilian honour in America.
已知和的半径分别为和，若，则和的位置关系是（ ）
- Yeah, ______ cars we use, ______ pollution there will be.
材料 庙号改革是北魏孝文帝改革的一项重要内容。公元398年，拓跋珪迁都平城，仿中原传统制度设立太庙，早先草原部落联盟时代的首领以“太祖”“高祖”等庙号受到祭祀，他们的子孙被封为王公，享有政治军事特权，成为北魏政权的统治支柱。孝文帝下令改革庙号，宣称按“宗有功、祖有德”的原则，推最先实现在中原进行统治的拓跋珪为太祖，不再为拓跋珪以前的祖先设庙祭拜。因太祖拓跋珪以后只有五位皇帝去世，为了不违“天子七庙”这一儒家礼制，孝文帝甚至前无古人地在太庙中为自己虚设一庙。庙号改定后，孝文帝下令，“非太祖子孙”及异姓封王、公、侯、伯者，皆降一等。
——据吕思勉《魏晋南北朝史》
如图，等腰梯形中，，，，，则_______．
求的值；
设这条直线与轴相交于点，求的面积．
（1）求证：；
（2）如图，当点是的外接圆圆心时，请判断四边形的形状，并证明你的结论．
先化简，再求值：，其中，．
A.  | B.  | C.  | D. \ |