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问题 问答题 简答题

中星9号卫星下行信号采用哪种极化，有什么特点？

答案

参考答案：

中星9号下行信号为左圆极化。

特点：

1、雨雪衰耗小，穿透电离层能力强

2、不受地球两级磁场产生的法拉第效应

3、安装调试时不用调整极化角方便用户接收。

改错题
此题要求改正所给短文中的错误。对标有题号的每一行作出判断：如无错误，在该行右边横线上画
一个勾（√）；如有错误（每行只有一个错误），则按下列情况改正：
此行多一个词：把多余的词用斜线划掉，在该行右边横线上写出该词，并也用斜线划掉。
此行缺一个词：在缺词处加一个漏字符号（∧），在该行右边横线上写出该加的词。
此行错一个词：在错的词下画一横线，在该行右边横线上写出改正后的词。
注意：原行没有错的不要改。
Dear Ralph,                                                  
    I'm a senior student. I'm getting well with a boy           
in my class. But I have fallen in love with him for almost   
half a year. He is shy boy, so I wrote him a letter first    
to express my feeling. He wrote back. In his letter        
he said, "We are students. Our task is study hard. Let us   
to wait and see whether we have any chance after graduation." 
So after graduation I telephoned to him, asking him       
about going out. But he said he didn't want to.           
He just wanted to sleep and watched TV.                 
What did you think I should do? Do you think              
I should continue to love him and give up?               
1.________     
2.________    
3.________    
4.________    
5.________   
6.________                                           
7.________   
                 
8.________   
9.________    
10.________   
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