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上路行驶的机动车未随车携带身份证的，交通警察可依法扣留机动车。
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第(24)至(26)题基于“学生-选课-课程”数据库中的如下三个关系： 学生基本信息：S(S#, SNAME,SEX,AGE) 选课信息：SC(S#, C#,GRADE) 课程信息：C(C#, CNAME, TEACHER) 若要求“查询选修了C2号课程的学生的学生号”，正确的关系代数表达式是 Ⅰ．π[S#](σ[C#=’C2’](SC)) Ⅱ．σ[C#=’C2’](π[S#](S×SC)) Ⅲ．σ[C#=’C2’](π[S#](SC))
When Susan Cox was adopted, she was raised in the American way happily.
Many communities offer ______ for bicultural children to learn about their native culture together in a fun environment.
The word conservation has a thrifty meaning. To conserve is to save and protect, to leave what we ourselves enjoy in such good condition as others (1)______ may also share the enjoyment. Our forefathers had no idea that human population would increase faster than the supplies of crude materials. Most of them, even (2)______ until very recently, have the foolish idea that the treasures were "limitless" and "inexhaustible". Most of the citizens of early generations knew little or (3)______ nothing about the complicated and the delicate system that runs all through the nature, which means that, as in a life body, an unhealthy condition of one part (4)______ will sooner or later be harmful to all others. (5)______ Fifty years ago nature study was not part of the school work. Scientific (6)______ forestry was a new idea; timber was still cheap at that time because it could be brought in any quantity from distant woodlands; soil destruction and river floods were not national problems; nobody had already studied long-term climate cycles (7)______ in relation with proper land use; even the word conservation had nothing of the (8)______ meaning that it has for us today. For the sake of ourselves and those who come after us, we must now set about (9)______ repairing the mistakes of our forefathers. Conservation should, however, be made (10)______ a part of everyone’s daily life. To know about the water table in the ground is just as important to us as a knowledge of the basic arithmetic formulas.
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