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【单选题】
坐标轴心是()。A.
物体重心
B.
空间XYZ三轴的交点
C.
所有物体公共中
D.
当前坐标系统的公共中心
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反馈参考答案：
举一反三
【单选题】How to approach Reading Test Part Four •This part of the Reading Test tests your vocabulary •Read the whole text quickly to find out what it is about. As you read, try to predict the words that might ...
A.
getting
B.
making
C.
setting
D.
running
【多选题】以下哪些是OFDM的特点:()
A.
低速并行传输：高速串行数据经串并转换后，分割成若干低速并行数据流;每路并行数据流采用独立载波调制并叠加发送
B.
抗衰落与均衡：由于OFDM对信道频带的分割作用，各个子载波占据相对窄的信道带宽，因而可以把它看作是平坦衰落信道;这样，OFDM技术就具有系统大带宽的抗衰落特性和子载波小带宽的均衡简单特性
C.
抗多径时延引起的码间干扰：引入循环前缀CP。只有多径时延扩展小于CP，码间干扰完全消除
D.
基于DFT实现：采用DFT进行OFDM信号调制和解调对频偏和相位噪声敏感，同步要求低
E.
峰值平均功率
【单选题】(There are) twelve people (take part) in the experiment, four (working) (as) a group.
A.
There are
B.
take part
C.
working
D.
as
【简答题】基带信号和宽带信号的传输各有什么特点
【单选题】How to approach Reading Test Part Four •This part of the Reading Test tests your vocabulary. •Read the whole text quickly to find out what it is about. As you read, try to predict the words that might...
A.
overestimate
B.
exaggerate
C.
outnumber
D.
supersede
【简答题】阅读路遥长篇小说《人生》
【单选题】How to approach Reading Test Part Four •This part of the Reading Test tests your vocabulary •Read the whole text quickly to find out what it is about. As you read, try to predict the words that might ...
A.
consolidating
B.
amalgamating
C.
incorporating
D.
integrating
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