皮皮学，免费搜题
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搜题
【单选题】
设一个关系模式为R(A,B,C),对应的关系内容为R={{1,10,50}, {2,10,60}, {3,20,72}, {4,30,60}},则δB>15(R)的运算结果中具有的元组个数为A.
1
B.
2
C.
3
D.
4
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举一反三
【单选题】Her gaze sharpened, as if she had seen something __________.
A.
peculiar
B.
characteristic
C.
unusual
【简答题】Her gaze sharpened, as if she had seen something __________.
【简答题】调式中的音、按照高低次序、由主音到主音排列起来就叫做（）
【单选题】The moment seemed to______out endlessly, his gaze travelling across her face, her neck, her shoulder, returning to her eyes.
A.
stretch
B.
expand
C.
skip
D.
slip
【简答题】Her gaze sharpened, as if she had seen something __________.
【简答题】The child was unaffected by the chaos because of her mother ’ s gaze.
【简答题】A prolonged gaze or stare in the United States is considered_____________.