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【单选题】
要建立一个约束,保证用户表(user)中年龄(age)必须在16岁以上,下面语句正确的是:A.
alter table user add constraint df_age DEFAULT(16)
B.
alter table user add constraint df_age DEFAULT(16) for age
C.
alter table user add constraint uq_age UNIQUE(age>16)
D.
alter table user add constraint ck_age CHECK(age>16)
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【单选题】有关 Southern blotting的正确描述是
A.
又称RNA印渍技术
B.
DNA转移至NC膜的速度取决于所带电荷
C.
主要用于RNA的定性和定量分析
D.
DNA也可以转移至滤纸上
E.
又称DNA印渍技术
【简答题】（毕竟） there are over twenty different meanings for 'fast' in the dictionary.
【简答题】完形填空。 Most people in the USA speak English. There are over 2000 languages spoken all over the world. You know that every language has 1 own words. 2 you want to learn a foreign language, you must know...
【多选题】社会主义核心价值观反映着我国社会主义基本制度的本质要求，渗透于（ ）的各个方面，是我国社会主义制度的内在精神之魂。
A.
经济
B.
政治
C.
文化
D.
社会
E.
生态建设
【单选题】All three of these following expressions refer to exactly the same people, but they will invoke different associations in the reader's mind: 1.There are over 2,000 vagrants in the city. 2.There are ov...
A.
positive, neutral, negative
B.
neutral, negative, positive
C.
negative, neutral, positive
D.
negative, positive, neutral
【简答题】句型转换。 1. There are over 60 students in his class. (改为同义句) There are 60 students in his class. 2. They go to school on their bikes. (改为同义句) They their bikes . 3. It takes about three years to build the...
【单选题】听力原文： There are over 3,000 languages that are used throughout the world today. Almost all of these languages belong to a much smaller number of language families. All of the languages within a languag...
A.
About 4,000.
B.
Over 300.
C.
Less than 2,000.
D.
Over 3,000.
【多选题】社会主义核心价值观反映着我国社会主义基本制度的本质要求渗透于()()()的各个方面,是我国社会主义内在精神之魂()。
A.
经济 政治
B.
文化 社会
C.
生态建设
D.
国际势力
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