单项选择题

SQL中CREATE TABLE语句的CHECK子句一般用于描述（）
A、实体完整性
B、参照完整性
C、用户定义完整性
D、关系的不变性

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多项选择题

Which of the following describes a learner who has declarative but not procedural knowledge? A、A learner who knows it's a must to put an s on the end of the verb when making third person singular declarative statements, but leaves off the s when making such statements. B、A learner who can state or declare the rule, but can't or doesn't use the rule when using the language to communicate. C、A learner who can't state the rule for the third person but does add s in statements unconsciously. D、A learner who is able to use the knowledge of language rules for communication.

单项选择题

A2 题型患儿男性,发热,食欲不振,消瘦伴有头痛,呕吐,疑为结核性脑膜炎,为明确诊断行PPD检察,请问在下列那种情况中,不应该出现PPD阴性的是 A、初次感染4~8周内 B、严重结核病 C、1岁以内婴儿 D、合并麻疹 E、合并重度营养不良

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