题目

       Imagine one day, the water taps in your house stop running. You have to buy water from shops. And still there isn’t enough for everyone. Your mother has to save the family’s shower water to do other things. Would you be able to stand that kind of life?        Probably not. But that’s what kids in Yemen are experiencing. Experts said Yemen is going to be the first country in the world to run out of water. According to a report, the capital, Sanaa, will run out of drinking water as early as 2025.        Because of the shortage, the government often cuts the 物体静止在水平地面上，在水平恒力F作用下，物体速度达到v时恒力F做功为W1，物体速度由V达到2V时力F做功为W2，则W1和W2之比为之比为      [　　]A、1：4     B、1：2     C、1：3      D、无法确定。