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问题 单项选择题

以下关于网络协议的描述中，错误的是______。

A．为保证网络中结点之间有条不紊地交换数据，需要制订—套网络协议

B．网络协议的语义规定了用户数据与控制信息的结构和格式

C．层次结构是网络协议最有效的组织方式

D．OSI参考模型将网络协议分为7个层次

答案

参考答案：B

解析：[知识点] 网络体系结构的基本概念[评析] 网络协议的语义，即需要发出何种控制信息，以及完成的动作与做出的响应。

多项选择题

下列现代的市场经济说法中正确的是()。

A、现代的市场经济是政府干预和市场经济相结合的混合经济

B、现代市场经济的发展在很大程度上取决于“划分市场与政府的合理界限是一个持久的问题”的有效解决

C、市场经济和社会上义基本制度的结合是不可行的

D、社会主义市场经济是市场经济与社会主义基本制度的结合

E、社会主义市场经济是市场经济的根本体现
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单项选择题

I got a job teaching special education at a school in Coachella, California, a desert town about 170 miles from home. It was no (1) job. Street gangs (2) around the school after dark.

"Be careful, " Dad warned me during one of my frequent weekend (3) home. He was concerned about my living (4) , but I needed to be on my own.

One evening, I stayed after school to rearrange my classroom. (5) , I turned out the light and closed the door. Then I (6) toward the gate. It was (7) ! I looked around. Everyone had gone home.

After (8) all the exits, I found just enough (9) to squeeze under a gate in the back of the school. Then I walked toward my car, parked in a field behind the building.Suddenly I heard voices. I (10) around and saw at least eight boys following me. (11) my pace, I reached into my shoulder bag to get my key. I (12) all over the inside of my handbag. But the key wasn’t (13) ! Dear Lord, please help me, I prayed (14) . Suddenly, my fingers touched a loose key in my purse. I didn’t even know if it was for my car, but I took it out and (15) it. It worked!I opened the door, slid in and locked it—just (16) the teenagers surrounded the car. Trembling , I started the engine and (17) away. When I returned to my apartment, the phone was ringing. It was my Dad. I didn’t tell him about my experience; I didn’t want to (18) him. "Oh, I forgot to tell you!" He said, "I had a (n) (19) car key made and slipped it into your purse—just (20) you ever need it.

13（）

A.there 

B.lost 

C.used 

D.inside
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