题目

甲、乙两个实心球质量相等，放入水中后，它们露出水面的体积分别为各自体积的1/3和1/2，那么（ ） A．甲、乙两物体的密度之比为4:3 B．甲、乙两物体的体积之比为3:2 C．甲、乙两物体所受的浮力之比为2:3 D．甲、乙两物体所受的浮力之比为1:1 答案：AD 甲、乙两球漂浮，所受浮力等于各自重力，因为质量相等，所以所受浮力相等，浮力之比为1:1，故C错误，D正确；甲、乙两球所受浮力相等，FA=FB=ρgVA=ρgVB；所以==，故B错误，密度之比==，故A正确。5、I know that you’ve both had a lot of fun these last two years on the campaign trail. But I also know that it hasn’t always been easy for you and Mom, and that as excited as you both are about that new puppy, it doesn’t make up for all the time we’ve been apart. I know how much I’ve missed these past two years, and today I want to tell you a little more about why I decided to take our family on this journey.   When I was a young man, I thought life was all about me――about how I’d make my way in the world, become successful, and get the things I want. But then the two of you came into my world with all your curiosity and mischief and those smiles that never fail to fill my heart and light up my day. And suddenly, all my big plans for myself didn’t seem so important anymore. And the greatest joy in my life was the joy I saw in yours. I realized that my own life wouldn’t count for much unless I was able to ensure that you had every opportunity for happiness and fulfillment in yours. In the end, girls, that’s why I wanted to be a candidate in the campaign: because of what I want for you and for every child in this nation.   I am so proud of both of you. I love you more than you can ever know. And I am grateful every day for your patience, poise, grace, and humor as we prepare to start our new life together in the White House.   71. Where is this passage taken from?   A. A speech about running for President.   B. An article about raising up children.   C. A letter from a parent to children.   D. A story about a teacher and students.   72. What did the writer mainly care for when he was young?   A. Great adventure.                                   B. Personal success.   C. Presidential election.                             D. Family happiness.   73. It can be inferred from Paragraph 2 that the author ____________.   A. was an ambitious young man   B. didn’t think his life counted much   C. loved all the children but the girls   D. thought the life was all about himself   74. Which one is NOT right about the feeling of the author to the girls?   A. Grateful.          B. Hopeful.                  C. Excited.            D. Beloved.   75. According to the passage, the author will __________ in the near future.   A. be a teacher in a new place   B. make a plan for a campaign   C. start a new life in the White House   D. take part in a special movement.