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【单选题】
设U是所有属性的集合，X、Y、Z都是U的子集，且Z=U—X—Y。下面关于多值依赖的叙述中，_______是不正确的。A.
若X→→Y，则X→→Z
B.
若X→Y，则X→→Y
C.
若X→→Y，且Y’∈Y，则X→→Y’
D.
若Z=Ф， 则X→→Y
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【简答题】It doesn't come as a surprise to you to realize that it makes no difference what you read or study if you can't remember it．You just waste your valuable time． 1 One dependable aid that does help you r...
【单选题】You forget ______ it to me. I haven't forgotten ______ it to you yesterday.
A.
to return to give
B.
returning giving
C.
to return giving
D.
returning to give
【单选题】— Would it bother you if I talked to you for a minute? — ____.
A.
Yes, please
B.
No, I don’t
C.
Yes, please don’t
D.
Not at all
【单选题】It to you whether I like it or not, because you never listen to me. [ ]
A.
makes a difference
B.
makes no difference
C.
makes some difference
D.
makes any difference
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