题目

下列说法正确的是 A．由于正丁烷和异丁烷分子间作用力大小不同，因而沸点不同 B．H2O汽化成水蒸气或者分解为H2和O2，都需要破坏共价键 C．Na2O2中含有共价键，所以Na2O2属于共价化合物 D．水晶和干冰都是共价化合物，所以他们的熔沸点相近 答案：A6．For over one hundred and fifty years，Americans of all social classes have worn blue jeans．（36）FWhether they are worn for work or for fashion today，Strauss'invention continues to be popular not only among Americans but also among people around the world．Levi Strauss was born in Germany in 1829．（37）AHe grew up in Kentucky before moving to New York in 1847．Before becoming an American citizen and moving to the West in 1853，Strauss worked in his brother's dry goods business．This gave him a chance to produce his famous invention．After the gold rush of 1949，Strauss decided to move to the West to seek his fortunes．Strauss did not want to be a person who searched an area for minerals．Instead，he knew he could make a good living by selling supplies to the miners．At first，he planned to sell sewing supplies and cloth．（38）DWhen he heard miners complaining that their clothes were easily broken or they usually tore their pockets during mining，he decided to use a special fabric to make pants for the miners．These pants proved so popular that he quickly ran out of materials to make more．In 1873，Strauss received a letter from a Jewish tailor named Jacob Davis who had invented a process of connecting pockets with copper rivets（铆钉）．This made the pants last a long time．Because Davis did not have the money to patent his idea，he offered to share it with Strauss if Strauss would agree to pay for the patent．（39）C．By the time Strauss died in 1902，he had made a great contribution to American fashion．（40）EThe business has been growing ever since and Levi Strauss'company is now one of the largest clothing companies in the world．A．As a young boy，he moved with his family to the United States．B．Nobody knew what kind of material was suitable．C．He did and Levi jeans have been made with metal rivets ever since．D．However，he did not get much business for those products．E．He also made a great contribution to America's clothing industry．F．Since they were invented by Levi Strauss，they have become a symbol of American consumer culture．G．As the business grew，Strauss got much money from it．