以下关于查询语句叙述错误的是______。
A．查询语句的功能是从数据库中检索满足条件的数据
B．查询的数据源可以来自一张表，或多张表甚至是视图
C．查询的结果是由0行或是多行记录组成的一个记录集合
D．不允许选择多个字段作为输出字段
参考答案：D
解析： 查询语句的功能是从数据库中检索满足条件的数据，查询的数据源可以来自一张表或多张表甚至是视图，查询的结果是由0行或多行记录组成的一个记录集合，并允许选择一个或多个字段作为输出字段。
Do you know how to study better and make your study more effective(有效的)？We all know that Chinese students usually study very hard for long 35 .This is very good, but it doesn’t 36 a lot, for an effective student must have enough sleep, enough rest and exercise. Every day you need to go out for a walk or visit some friends or some nice places. It’s good for your study. When you return 37 your studies, your mind will be refreshed(清醒) and you’ll learn more 38 study better. Psychologists(心理学家) 39 that learning takes place in this way. Here take English learning 40 an example. In the first few months you can make a lot of progress and you feel happy. Then your language study seems 41 the same. So you will think you’re learning 42 and you may give up. This can last for days or even weeks, yet you needn’t give up. At some point your language study will take another big 43 . You’ll see that you really have been learning all along. If you get enough sleep, food, rest and exercise, studying English can be very effective and interesting. Don’t 44 along the way. Learn slowly and you’re sure to get a good result.
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