皮皮学，免费搜题
登录
搜题
【单选题】
下列符合不孕症的定义是:
A.
女性未避孕,有正常性生活,至少6个月而为受孕者
B.
女性未避孕,有正常性生活,至少12个月而未受孕者
C.
女性未避孕,有正常性生活,至少2年而未受孕者
D.
女性未避孕,有正常性生活,至少3你啊而未受孕者
E.
女性未避孕,结婚1年未受孕者
拍照语音搜题，微信中搜索"皮皮学"使用
参考答案：
参考解析：
知识点：
.
..
皮皮学刷刷变学霸
举一反三
【单选题】关于码的正确描述是
A.
关系中每个单独属性均可作为码
B.
码也称关键字，它能够唯一标识一个实体。
C.
任意属性的组合均可作为码
D.
由属性组合构成的码，其各个元组的分量值均相等
查看完整题目与答案
【单选题】The main difficulty with teaching is the large _____ of work.
A.
number
B.
content
C.
part
D.
volume
查看完整题目与答案
【单选题】What is the main difficulty in recycling?
A.
Searching for the related information.
B.
Changing people's habits on rubbish disposing
C.
The fact that too much rubbish is produced.
查看完整题目与答案
【简答题】根据中文意思,写出英文单词或词组 感应电动机
查看完整题目与答案
【单选题】关于外码概念正确描述是
A.
外码与码一样不能出现重复值
B.
外面的取值是某个关系的主码值但可以重复
C.
外码不可以是属性组
D.
外码的取值不能是本关系的主码值
查看完整题目与答案
【简答题】You must cultivate good manners and behave like a gentleman. ( 培养 )
查看完整题目与答案
【简答题】请按照task2的要求,将答案按照视频要求正确朗读,提交语音。如: The main difficulty I have in time management is how to 2.根据自己的情况完成task1的测试并提交算出来的总分。如:task1 我的得分是xxx
查看完整题目与答案
【单选题】关于码的正确描述是
A.
主码都是由属性组构成的
B.
主码与候选码共同点是无重复值的属性
C.
候选码都是由单一属性构成的
D.
一个关系只能有一个候选码
查看完整题目与答案
【单选题】The main difficulty the writer had in reading in her 7th grade was that ______.
A.
she often forgot her school reading assignments
B.
she had difficulty reading with comprehension
C.
she had a poor vocabulary and very bad grammar
D.
she always looked elsewhere when asked to read
查看完整题目与答案
【单选题】The main difficulty in solving the food problem is ______.
A.
backward social and economical background
B.
lack of information about food needs
C.
conflicts between 'haves' and 'haves-not'
D.
lack enough funds to modernize agriculture
查看完整题目与答案
相关题目：
【单选题】关于码的正确描述是
A.
关系中每个单独属性均可作为码
B.
码也称关键字，它能够唯一标识一个实体。
C.
任意属性的组合均可作为码
D.
由属性组合构成的码，其各个元组的分量值均相等
查看完整题目与答案
【单选题】The main difficulty with teaching is the large _____ of work.
A.
number
B.
content
C.
part
D.
volume
查看完整题目与答案
【单选题】What is the main difficulty in recycling?
A.
Searching for the related information.
B.
Changing people's habits on rubbish disposing
C.
The fact that too much rubbish is produced.
查看完整题目与答案
【简答题】根据中文意思,写出英文单词或词组 感应电动机
查看完整题目与答案
【单选题】关于外码概念正确描述是
A.
外码与码一样不能出现重复值
B.
外面的取值是某个关系的主码值但可以重复
C.
外码不可以是属性组
D.
外码的取值不能是本关系的主码值
查看完整题目与答案
【简答题】You must cultivate good manners and behave like a gentleman. ( 培养 )
查看完整题目与答案
【简答题】请按照task2的要求,将答案按照视频要求正确朗读,提交语音。如: The main difficulty I have in time management is how to 2.根据自己的情况完成task1的测试并提交算出来的总分。如:task1 我的得分是xxx
查看完整题目与答案
【单选题】关于码的正确描述是
A.
主码都是由属性组构成的
B.
主码与候选码共同点是无重复值的属性
C.
候选码都是由单一属性构成的
D.
一个关系只能有一个候选码
查看完整题目与答案
【单选题】The main difficulty the writer had in reading in her 7th grade was that ______.
A.
she often forgot her school reading assignments
B.
she had difficulty reading with comprehension
C.
she had a poor vocabulary and very bad grammar
D.
she always looked elsewhere when asked to read
查看完整题目与答案
【单选题】The main difficulty in solving the food problem is ______.
A.
backward social and economical background
B.
lack of information about food needs
C.
conflicts between 'haves' and 'haves-not'
D.
lack enough funds to modernize agriculture
查看完整题目与答案