下列关于首位度和城市指数表述正确的是( )。
①一国最大城市与第二位城市人口的比值，即首位度；
②首位度一定程度上代表了城市体系中的城市人口在最大城市的集中程度，不免以偏概全；
③按照位序一规模的原理，正常4城市指数和11城市指数都应是1。
A．①②③
B．②③
C．①②
D．①③
参考答案：A
解析：[试题解析] 4城市指数S=P1/(P2+P3+P4)；11城市指数11城市指数S=2 P1/(P2+P3+P4+……P11)。 P1，P2，……P11，为城市按规模从大到小排序后，某位序城市的人口规模。显然4城市指数和11城市指数比只考虑两个城市更能全面地反映城市规模分布的特点。
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| In 1989 an 8.2 earthquake almost flattened Los Angeles, killing over 30,000 people in less than four minutes. A father rushed to where his son was 1 to be, only to discover that the building was flattened. But he remembered the 2 he had made his son: "I'll always be there for you!" Tears began to fill his eyes. Although it looked 3 , he remembered his words. 4 his son's classroom would be in the back right corner of the building, he rushed there and started 5 . Other parents tried to pull him off what was left of the school, saying " It's too late! They're all dead! You can't 6 !" To each he 7 : "Are you going to help me?" And then he went back to his digging. The fire fighter 8 and tried to pull him away: "Fires are breaking out, explosions are happening everywhere. You're 9 ."To which this loving, 10 father asked:"Are you going to help me?" He went on 11 he needed to know,"Is my boy alive or is he dead?" He dug for eight hours…l2 hours…36 hours…then, in the 38th hours, he pulled back a large stone and 12 his son. He 13 : "ARMAND!"He heard back:" Dad?It's me, Dad! I told the other kids not to 14 . I told them that if you were 15 , you'd save me and when you saved me, they'd be saved. You 16 , no matter what happens, I'll always be there for you!" "What's going on in there?" the father asked. "There are l4 of us 17 out of 33, Dad. We're scared but 18 you're here. When the building collapsed, it 19 a triang1e (三角形), and it saved us." " 20 , boy!" "Let the other kids out first, because I know you'll get me! I know you'll always be there for me!" | ||||
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