题目

下图表示的是某植物的非绿色器官呼吸时O2的吸收量和CO2的释放量之间的相互关系，其中线段XY=YZ，则在氧浓度为a时［    ］A．有氧呼吸比无氧呼吸消耗的有机物多     B．有氧呼吸比无氧呼吸释放的能量多 C．有氧呼吸比无氧呼吸释放的二氧化碳多   D．有氧呼吸和无氧呼吸释放的能量相等 答案：B 解析: 略 阅读理解 　　To many Americans, Labor Day marks the end of the summer, a day off from work and school, and one last chance to relax．But Labor Day is much more than just a day off．It represents a very important victory for laborers everywhere．The holiday is a celebration of the social and economic achievements of American workers． 　　More than a century ago, workers were forced to deal with harsh conditions．They were paid very little, and they often worked 10-to 12-hour days．Men, women and even small children were forced to work even when they were sick．Tired of long hours and dangerous conditions, workers began organizing themselves into labor unions．On top of fighting for higher pay and shorter workdays, they also fought for the rights of children．The workers wanted employers to place limits on the age of their workers so that small children were not overworked or hurt in factories． 　　A New York City carpenter named Peter McGuire is credited for coming up with the idea for Labor Day．In 1872, after working many hours under poor conditions, McGuire rallied 100,000 workers to go on strike．The workers marched through the streets of New York City, demanding a better work environment．McGuire spent a decade fighting for workers' rights．In 1882, he proposed the idea to create a special holiday for workers．On Tuesday, September 5, 1882．more than 10,000 workers hit the streets of New York City for the first ever Labor Day parade．Two years later the celebration was moved to the first Monday in September．And in 1894, Congress passed a law making Labor Day a national holiday． 　　Americans celebrated the first Labor Day holiday with a parade, picnics and fireworks．Today, many people hit the road to enjoy the last of their summer vacation．Others enjoy the long weekend with picnics, backyard barbecues or just rest and relaxation．However you spend Labor Day, remember that the holiday is a time to pay tribute(致敬)to the workers who have made America what it is today． (1) What do we know from Paragraph 1? [　　] A． Americans have more than a day off on Labor Day． B． Many countries in the world celebrate Labor Day． C． Labor Day has a deep meaning for American laborers． D． Labor Day shows the social and economic power of America． (2) What is Paragraph 2 mainly about? [　　] A． American workers' fighting against their employers． B． The bad life that American workers 1ed． C． How American employers treated their workers． D． The life that American workers ever expected． (3) The underlined word “rallied” in Paragraph 3 can be replaced by“________”． [　　] A． persuaded B． supported C． rewarded D． gathered (4) Which of the following statements is TRUE according to the passage? [　　] A． There were about 100,000 workers in New York City in 1872． B． Labor Day became a national holiday in 1884． C． In 1872 Labor Day was first put forward by McGuire． D． The first ever Labor Day parade was held in 1882． (5) According to the author, while spending Labor Day, Americans should feel ________． [　　] A． surprised B． thankful C． dissatisfied D． superior