题目

下列实验操作中错误的是（ ）A.实验产生的废液应倒入指定的容器内B.可燃性气体点燃之前必须检验其纯度C.给玻璃仪器加热时都需垫石棉网D.实验室制取气体，要先对装置的气密性进行检查 答案：【答案】C【解析】本题考查规范的实验操作。A、实验产生的废液应倒入指定的容器内，以防止污染环境，故A不符合题意；B、为防止发生爆炸，可燃性气体点燃之前必须检验其纯度，故B不符合题意；C、给玻璃仪器加热时不一定都需垫石棉网，如试管可以直接加热，故C符合题意；D、实验室制取气体时Americans have always been interested in their Presidents' wives. Many First Ladies have been remembered because of the ways they have influenced their husbands. Other First Ladies have made the history books on their own. At least two First Ladies, Bess Truman and Lady Bird Johnson, made it their business to send signals during their husbands speeches. When Lady Bird Johnson thought her husband was talking too long, she wrote a note and sent it up to the platform. It read, "It's time to stop ! " And he did.  Once Bess Truman didn't like what  her husband was saying on television, so she phoned him and said, "If you can't talk more politely than that in public, you come right home. " It was First Lady Helen Taft's idea to plant the famous cherry trees in Washington, D. C. Each spring these blossoming trees attract thousands of visitors to the nation's capital Mrs. Taft also influenced the male members of her family and the White House staff in a strange way: she convinced(说服)them to shave off their beards(胡须) ! Shortly after President Woodrow Wilson suffered a stroke (中风),  Edith Wilson unofficially took over most of the duties of the Presidency until the end of her husband's term  Earlier, during World War I, Mrs.  Wilson had sheep brought onto the White House lawn to eat t e grass. The sheep not only kept the lawn cut. but provided wool for an auction(拍卖) held by the First Lady.  Almost$ 100,000 was raised for the Red Cross. One of the most famous First Ladies was Eleanor Roosevelt, the wife of President Franklin D. Roosevelt. She was active in political and. social causes throughout her husband's term in office After his death, she became famous for her humanitarian(人道主义的) work in the United Nations. She made life better for thousands of needy people around the world.小题1:Why have First Ladies been remembered?A．They are the wives of the presidents.B．They are made up of history books.C．Americans are interested in them.D．They have an effect on their husbands.小题2:The examples mentioned in Paragraph 2 show thatA. the two wives did business without their husbandsB. the two wives influenced the presidents' speechesC. the two wives didn't like their husbands to make speechesD the presidents' speeches were often interrupted by their wives.小题3:Who did the most meaningful work among the first ladies?A．Lady Bird Johnson.B．Mrs. Wilson.C．Eleanor Roosevelt.D．Helen Taft小题4:Which of the following is considered a strange thing the First Lady did?A. Raise sheep on the White House lawn to get money for the Red Cross.B. Take over most of the duties throughout their husbands' Presidency.C. Plant the cherry trees in Washington, D. C. to attract more visitorsD. Persuade the men staff in the White House to shave off their beards.小题5:How many First Ladies are mentioned in this passage?A．3B．4.C．5D．6.