● 关系 R、S 如下图所示，关系代数表达式 ))S R ((6 1 5,3 ,4 × ＜ σ π 的输出结果与（34） 等价，该表达式与 （35） 等价。若对关系 R、S 进行自然连接，所得关系的属性列数和元组个数分别为 （36） 。
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Why doesn’t Allegheny College plan to drop merit aid entirely？
A. Raising tuitions have made college unaffordable for middle-class families.
B. With rising incomes, fewer students are applying for need-based aid.
C. Many students from middle-income families have come to rely on it.
D. Rising incomes have disqualified many students for need-based aid.
An example illustrating the general trend of universities' globalization is
A. Yale's collaboration with Fudan University on genetic research
B. Yale's helping Chinese universities to launch research projects
C. Yale's student exchange program with European institutions
D. Yale's establishing branch campuses throughout the world
Normal 0 7.8 磅 0 2 false false false
A. increase their income by working overtime
B. improve their expertise and service
C. make various deals with specialists
D. see more patients at the expense of quality
Why did Rebecca want to enter this year's writing contest？
A） She believed she possessed real talent for writing.
B） She was sure of winning with her mother's help.
C） She wanted to share her stories with readers.
D） She had won a prize in the previous contest.
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