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问题 选择题
已知集合A={直线}，B={平面}，C=A∪B，若a∈A，b∈B，c∈C，给定下列命题：
①
a⊥b
c⊥b
⇒a∥c；②
a⊥b
c∥b
⇒a⊥c；③
a∥b
c∥b
⇒a∥c；④
a∥b
c⊥b
⇒a⊥c．
其中一定正确的是（　　）
A．①②B．②③C．③④D．②
答案

∵集合A={直线}，B={平面}，C=A∪B，若a∈A，b∈B，c∈C，

则a为直线，b为平面，c可能是直线，也可能是平面

若c为直线

则①

a⊥b
c⊥b
⇒a∥c正确；

②

a⊥b
c∥b
⇒a⊥c正确；

③

a∥b
c∥b
⇒a∥c错误；

④

a∥b
c⊥b
⇒a⊥c正确．

若c为平面

则①

a⊥b
c⊥b
⇒a∥c错误；

②

a⊥b
c∥b
⇒a⊥c正确；

③

a∥b
c∥b
⇒a∥c错误；

④

a∥b
c⊥b
⇒a⊥c错误．

故只有②一定正确

故选D

阅读理解

小题1:What’s the purpose of the author in writing the text?

A．To introduce his favorite food to the readers．

B．To introduce some steakhouses in New York．

C．To provide guidance on eating in America．

D．To offer some advice on running restaurants．小题2:Which of the following statements is true according to the text?

A．All the four restaurants are open on weekends．

B．Bruno is the owner of Peter Luger’s Steakhouse．

C．The beef in AJ Maxwell’s is from South Dakota．

D．You can enjoy family hospitality in Ben and Jack’s．小题3:If you don’t like having dinner indoors，you can go to _____________．

A．Aged—New York City

B．Club A Steakhouse

C．Ben and Jack’s on 5th Ave

D．AJ Maxwell’s Steakhouse小题4:If you have to drive，you are NOT advised to go to ____________．

A．255 5th Avenue，New York

B．240 East 58th St．，New York

C．2398 Broadway，New York

D．57 West 48th Street，New York小题5:What do the four restaurants have in common?

A．Restaurant style．

B．Privacy protection．

C．Minimum expense．

D．Seafood service．
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单项选择题

患者，男性，45岁，左股骨颈骨折术后2个月入康复科功能训练。

若两下肢长度相差4cm以上，则出现

A．短腿步态

B．剪刀步态

C．减痛步态

D．画圈步态

E．慌张步态膝塌陷步态
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