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问题 不定项选择

下列选项中有关地表水的说法正确的是（）。

A.河川径流包括地面径流和地下径流两部分

B.在径流形成过程中，常常将从降雨到径流形成称为汇流阶段

C.径流系数指流域出口断面流量与流域面积的比值

D.河流某断面以上区域内，由降水所产生的地面与地下径流均通过该断面流出时，这块区域称作流域面积

答案

参考答案：A, D

解析：B项错误，在径流形成过程中，常常将从降雨到径流形成称为产流阶段；把坡面漫流及河网汇流称为汇流阶段。C项错误，径流系数指某一时段内径流深与相应降雨深的比值；径流模数指流域出口断面流量与流域面积的比值。

单项选择题

临床食管癌多见于哪一部分

A．颈部
B．胸部上段
C．胸部下段
D．胸部中段
E．以上都是
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填空题


The United States counts its population every ten years, and each census reveals that the racial and ethnic mix is changing dramatically, so by the year 2050, the "average" American will not be descended from (1) , but the majority of U. S. residents will trace (2) ancestry to Africa, Asia, the Hispanic world, the Pacific Islands, or the Middle East. Once the United States was a microcosm of European nationalities, (3) the United States is a microcosm of the world. The United States is (4) considered a "melting pot" society by many of its residents. (5) , many people prefer the term "salad bowl." They use this (6) to describe American society. American society will soon be (7) nonwhite. "Melting pot" implies that the different ethnic groups blend together (8) one homogeneous (9) , "salad bowl" (10) that nationalities, like the ingredients in a mixed green salad, retain their cultural (11) . Earlier generations of (12) believed they had to learn English quickly not only to survive but also for (13) .
Now, many immigrant groups do not (14) the same need. Because there are many places in America (15) you can work, shop, get medical care, marry, divorce and die without knowing English. (16) , Chinatown in San Francisco and New York. Also, Los Angeles has many Vietnamese immigrants and immigrants from Mexico. (17) , many immigrant groups want their children to know their (18) culture. Many Hispanics, for instance, want their children to learn (19) English and Spanish and study the Spanish language in school. They are fighting for the (20) to bilingual education in many communities. In many communities they are in the majority.
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