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【单选题】
服务与协议是完全不同的两个概念,下列关于它们的说法错误的是()。
A.
协议是水平的,即协议是控制对等实体间通信的规则。服务是垂直的,即服务是下层向上层通过层间接口提供的。
B.
在协议的控制下,两个对等实体间的通信使得本层能够一层提供服务。要实现本层协议,还需要使用下面一层所提供的服务。
C.
协议的实现保证了能够一层提供服务。
D.
OSI 将层与层之间交换的数据单位称为协议数据单元PDU.OSI 将层与层之间交换的数据单位称为服务数据单元 SDU.OSI 将对等层饮之间传送的数据单位称为该层的协议数据单元 PDU.
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参考答案：
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【单选题】听力原文： Should a person own a car? This is an important question. In a large urban area, there are some good reasons for owning a car. Firstly, a car allows a person to move around freely. With a car th...
A.
Buses and trains are too crowded.
B.
A person can move around freely.
C.
It is easy to maintain cars.
D.
A driver is usually safe in his car.
查看完整题目与答案
【单选题】听力原文： Should a person own a car? This is an important question. In a large urban area, there are some good reasons for owning a car. First, a car allows a person to move around freely. With a car ther...
A.
Buses and trains are too crowded.
B.
A person can move around freely.
C.
It is easy to maintain cars.
D.
A driver is usually safe in his ear.
查看完整题目与答案
【单选题】This is an important concept to_______.
A.
get over
B.
get across
C.
get away
D.
get off
查看完整题目与答案
【单选题】Which of the following is NOT mentioned as a problem the counselors can help with?
A.
Strained relationship with boyfriend or girlfiend.
B.
Financial difficulties.
C.
Excessive tress of work.
D.
Death of a close.
查看完整题目与答案
【多选题】武器系统工程的主要构成要素包括哪些?
A.
以武器系统为研究对象
B.
研究实现武器系统优化的科学方法
C.
研究武器系统的整体目标
D.
将科学技术和工程的基本理论、方法、成果应用于武器系统
查看完整题目与答案
【单选题】影响施工工程项目的因素主要包括五大方面，即工程中的4M1E。主要指（ ）。
A.
人材料机械方法和环境
B.
人（MAn）、材料(MAteriAl)、工具（MeAns）、方法(MethoD)和环境(Environment)
C.
人（MAn）、工具（MeAns）、机械(MA
D.
hine)、方法(MethoD)和环境(Environment)
E.
工具（MeAns）、材料(MAteriAl)、机械(MAChine)、方法(Metho
F.
)和环境(Environment)
查看完整题目与答案
【简答题】College counselors say that as schools get choosier, parents have grown more resigned to the realities of kids’ prospects.
查看完整题目与答案
【单选题】The counselors ______ the dormitory during the fire drill.
A.
scanned
B.
scrutinized
C.
explored
D.
swept
查看完整题目与答案
【单选题】—Why are you _____ this morning? This is an important meeting. —Sorry, I stayed up and sorted out the materials for the meeting last night. [     ]
A.
asleep
B.
impatient
C.
sleepy
D.
excited
查看完整题目与答案
【单选题】Counselors say the ranks are growing as teens get__________ Web-enabled devices like cell phones and computer games.
A.
hooked on
B.
hook
C.
result from
D.
accompany
查看完整题目与答案
相关题目：
【单选题】听力原文： Should a person own a car? This is an important question. In a large urban area, there are some good reasons for owning a car. Firstly, a car allows a person to move around freely. With a car th...
A.
Buses and trains are too crowded.
B.
A person can move around freely.
C.
It is easy to maintain cars.
D.
A driver is usually safe in his car.
查看完整题目与答案
【单选题】听力原文： Should a person own a car? This is an important question. In a large urban area, there are some good reasons for owning a car. First, a car allows a person to move around freely. With a car ther...
A.
Buses and trains are too crowded.
B.
A person can move around freely.
C.
It is easy to maintain cars.
D.
A driver is usually safe in his ear.
查看完整题目与答案
【单选题】This is an important concept to_______.
A.
get over
B.
get across
C.
get away
D.
get off
查看完整题目与答案
【单选题】Which of the following is NOT mentioned as a problem the counselors can help with?
A.
Strained relationship with boyfriend or girlfiend.
B.
Financial difficulties.
C.
Excessive tress of work.
D.
Death of a close.
查看完整题目与答案
【多选题】武器系统工程的主要构成要素包括哪些?
A.
以武器系统为研究对象
B.
研究实现武器系统优化的科学方法
C.
研究武器系统的整体目标
D.
将科学技术和工程的基本理论、方法、成果应用于武器系统
查看完整题目与答案
【单选题】影响施工工程项目的因素主要包括五大方面，即工程中的4M1E。主要指（ ）。
A.
人材料机械方法和环境
B.
人（MAn）、材料(MAteriAl)、工具（MeAns）、方法(MethoD)和环境(Environment)
C.
人（MAn）、工具（MeAns）、机械(MA
D.
hine)、方法(MethoD)和环境(Environment)
E.
工具（MeAns）、材料(MAteriAl)、机械(MAChine)、方法(Metho
F.
)和环境(Environment)
查看完整题目与答案
【简答题】College counselors say that as schools get choosier, parents have grown more resigned to the realities of kids’ prospects.
查看完整题目与答案
【单选题】The counselors ______ the dormitory during the fire drill.
A.
scanned
B.
scrutinized
C.
explored
D.
swept
查看完整题目与答案
【单选题】—Why are you _____ this morning? This is an important meeting. —Sorry, I stayed up and sorted out the materials for the meeting last night. [     ]
A.
asleep
B.
impatient
C.
sleepy
D.
excited
查看完整题目与答案
【单选题】Counselors say the ranks are growing as teens get__________ Web-enabled devices like cell phones and computer games.
A.
hooked on
B.
hook
C.
result from
D.
accompany
查看完整题目与答案
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