在数字广播电视系统中，（）的作用是将信源发出的模拟信号转换成_爱下问搜题

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问题单项选择题

在数字广播电视系统中，（）的作用是将信源发出的模拟信号转换成有规律的、适应信道传输的数字信号。

A.编码器

B.调制器

C.解调器

D.解码器

答案

参考答案：A

完形填空

完型填空（共20小题，每题1分，满分20分）
Good Work Ethics （规范）
When I was younger, about 14, I was already ready to work．My father was a dairy man and he had been working his entire life．For him, getting up at 5 a．m．and working a couple of hours before I went to school, and then   36  more after school until there was not enough37   to see, were normal．
My father considered putting good work ethics in me to be very   38 ．He began to show me these, not through   39 , but through his actions．He would not 40  a job until it was done．He   41  put his all into everything he did．   42  , he showed me this not just in working, but in everything．Like when I was in soccer, I wanted to 43 a game once．and he explained to me-that I had made a 44  and that even if I just skipped one game, then I did not 45   to play the rest of the games．
So the day I started my first job at the age of 14, I was 46  to show my father that I could do it well, and that I was not going to 47 . My entire 48  was to make my father proud of me. I knew that     ___49  I did, he would not say it in words, but he would show it．My first job was doing   50   for a company．As most of you know, construction is not an easy job, especially being so   51 _. When someone as young as I was started working, they would either __52  or get stronger．I got stronger．I worked the   53  I had been taught and I gave that day everything I had．In the end, my boss was impressed．He even called to tell my parents what a good worker I was, and my parents' eyes   __54  ．From that day on I have worked every job to my full   55  , because that day defined （explain the truth of）my life．It defined how I was going to work, and I will always stick to it．

B．improvement

A．construction

B．negotiation

C．communication

问答题简答题

在定向井、大斜度施工中，经常在滑动钻进时出现托压现象，请分析可能的原因和解决方法？