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问题 选择题

已知集合A＝{x∈R||x|≥2}，B＝{x∈R|x2－x－2＜0}，且R为实数集，则下列结论正确的是(  )

A．A∪B＝R

B．A∩B≠∅

C．A⊆(∁RB)

D．A⊇(∁RB)

答案

答案：C

集合A＝{x|x≥2或x≤－2}，B＝{x|－1＜x＜2}，所以A⊆(∁RB)．

单项选择题

磁盘上内部磁道较外部磁道短，在处理存储数据时( )。

A．内部磁道存储信息比外部磁道存储信息少

B．无论哪条磁道，存储信息均相同

C．内部磁道扇区少，使它的存储信息少于外部磁道

D．各磁道扇区数相同，但内部磁道上每扇区记录信息少
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填空题

Beijing: The United States and North Korea had their first ______ in four months here this afternoon as part of the ______ negotiations on how to end North Korea’s nuclear program, but diplomats played down prospects for______. James A. Kelly, assistant ______, and Kim Yong Ⅱ, North Korea’s deputy foreign minister, met ______ of formal discussions, ______ on direct dialogue that began after a stormy meeting ______ in which North Korea warned that it was moving quickly to ______ nuclear arms. The Bush administration had insisted ______ that it would only hold talks with North Korea ______ because, it argued, only ______ pressure would persuade North Korea to______. It got its way when North Korea dropped its insistence on ______ and agreed, after extensive efforts by China, to hold unusual simultaneous negotiations with ______,______,______ and ______ as well as the United States. Though Bush administration officials had not ______ talking privately with the North Koreans during______, the fact that Mr. Kelly and Mr. Kim met on the first day was seen as a sign of ______ by the American side.
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