假设有如下的关系R和S: 若关系R和S的关系代数操作的结果如下,这是执行了

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问题:

假设有如下的关系R和S:



若关系R和S的关系代数操作的结果如下,这是执行了


考点:计算机等级考试数据库技术三级数据库技术笔试
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She is good _____________ drawing.[ ]

A. in

B. on

C. at

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()对人力资本理论的贡献在于通过对经济增长因素的分析和计量而计算出人力资本投资的作用。

A.爱德华·丹尼森

B.雅可布·明瑟

C.西奥多·W·舒尔茨

D.加里•S•贝克尔

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大肠埃希菌不能引起下列哪种疾病()

A.败血症

B.泌尿系感染

C.胃肠炎

D.旅行者腹泻

E.流行性脑脊髓膜炎

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All the definitions(定义) and facts in a dictionary or book do not convey what friendship is really about. It cannot be understood through   36 . The only way to understand friendship is through experience, which   37  all the senses.
Friendship can be seen. It is seen in an old couple sitting in the park holding hands. It is seen in a child freely   38  the last cookie. It is not   39  to see friendship; it is always there for eyes that can see.
Friendship can be heard. It is heard in the words of two friends squeezing in lunch together on an extremely   40  day although they have a lot of things to do. It is the way they   41  each other, not the words. Friendship can be heard by those willing to listen.
Friendship is   42  in a touch. It is a pat on the back from a teammate, a high five between classes, and the wet kiss from the family dog. The touch   43  more than words or gestures. It is   44  understood and clearly shows the feelings.
Friendship has a taste. It tastes like homemade bread: the ingredients all measured and planned, then carefully   45 , then the quiet   46  as the dough(生面团) rises. Hot from the oven, the bread tastes more than the sum of its ingredients   47  there are the thoughts of the baker as her hands mix the flour or her   48  as she waits for the dough to rise.  49  and unmeasured, this is the ingredient that   50 . Warm, fresh from the oven, the difference you taste is   51 .
Friendship has a smell. It smells like the slightly burnt cookies your brother made especially for you. It smells like your home when   52  it after being away for a long tome. Friendship has   53  smells.
Finally, more than the other senses, friendship is a(n)  54  of the heart. It is the language of the heart --- a language that, whether seen, felt, heard, or tasted, is understood by the   55 . Like air fills the lungs, friendship fills the heart, allowing us to experience the best life has to offer: a friend.
小题1:
A.readingB.studyingC.wordsD.gestures
小题2:
A.expectsB.involvesC.affectsD.expresses
小题3:
A.eatingB.holdingC.choosingD.sharing
小题4:
A.commonB.formalC.difficultD.private
小题5:
A.busyB.toughC.badD.important
小题6:
A.look atB.talk toC.care for D.play with
小题7:
A.feltB.givenC.discoveredD.remembered
小题8:
A.understandsB.explainsC.communicatesD.knows
小题9:
A.perfectlyB.instantlyC.hopefullyD.thankfully
小题10:
A.tastedB.preparedC.mixedD.supplied
小题11:
A.waitingB.workingC.changeD.competition
小题12:
A.andB.becauseC.untilD.unless
小题13:
A.patienceB.confidenceC.toleranceD.dependence
小题14:
A.UnfinishedB.UncoveredC.UnseenD.Unmoved
小题15:
A.comes to lifeB.makes the differenceC.makes senseD.takes effect
小题16:
A.happinessB.comfortC.friendshipD.hardship
小题17:
A.winning backB.stepping intoC.helping outD.carrying on
小题18:
A.strongB.strangeC.naturalD.various
小题19:
A.experienceB.thoughtC.rewardD.result
小题20:
A.partnersB.sensesC.heartD.family
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排水通气管不得与风道或烟道连接,其安装高度应符合什么要求?

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