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问题 选择题

已知集合M=｛a2, a+1,-3｝, N=｛a-3, 2a-1, a2+1｝, 若M∩N=｛-3｝, 则a的值是(     )                                                     

A  -1         B   0            C   1             D   2

答案

A 

M∩N=｛-3｝ N=｛a-3, 2a-1, a2+1｝

若a-3=-3, 则a=0,此时M="{0,1,-" 3}   ,N="{-" 3,- 1,1} 则 M∩N=｛-3,1｝故不适合

若2a-1=-3,则a=" -" 1,此时M="{1," 0,- 3}, N="{-" 4,- 3, 2}

若a2+1=-3,此方程无实数解

单项选择题

Strange things have been happening to England. Still (1) from the dissolution of the empire in the years (2) World War Ⅱ, now the English find they are not even British. As the cherished "United Kingdom" breaks into its (3) parts, Scots are clearly (4) and the Welsh, Welsh. But who exactly are the English What’s left of them, with everything but the (5) half of their island taken away

Going back in time to (6) roots doesn’t help. First came the Celts, then the Romans, then Angles, Saxons, Jutes, Danes. Invasion after invasion, until the Norman Conquest. English national identity only seemed to find its (7) later, on the shifting sands of expansionism, from Elizabethan times onwards. The empire seemed to seal it. But now there’s just England, (8) of a green island in the northern seas, lashed by rain, scarred by two (9) of vicious industrialization fallen (10) dereliction, ruined, as D．H. Lawrence thought, by "the tragedy of ugliness," its abominable architecture.

Of all English institutions, the one to (11) on would surely be the pub. Shelter to Chaucer’s pilgrims, home to Falstaff and Hal, throne of felicity to Dr. Johnson, the pub- that smoky, yeasty den of jollity-is the womb of (12) , if anywhere is. Yet in the midst of this national (13) crisis, the pub, the mainstay of English life, a staff driven (14) into the sump of history, (15) as the Saxons, is suddenly dying and evolving at (16) rates. Closing at something like a rate of more than three a day, pubs have become (17) enough that for the first time since the Domesday Book, more than half the villages in England no longer have one. It’s a rare pub that still (18) , or even limps on, by being what it was (19) to be: a drinking establishment. The old (20) of a pub as a place for a "session," a lengthy, restful, increasingly tipsy evening of swigging, is all but defunct.

6（）

A.look

B.trace

C.search

D.hunt
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单项选择题

下列有关工程结算的说法中，( )是正确的。

A．工程结算是由施工单位编制的确定工程实际造价的技术经济文件
B．工程结算是由建设单位编制的确定工程实际造价的技术经济文件
C．工程结算是由施工单位编制的用来综合反映竣工建设项目或单项工程的建设成果和财务情况的总结性文件
D．工程结算是由建设单位编制的用来综合反映竣工建设项目或单项工程的建设成果和财务情况的总结性文件
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