问题 单项选择题

关于VHF电台在同一地点,不同的电台的频道间隔和不同设备的天线最小间隔的说法,不正确的是()

A、频道间隔最好在550KHz以上,天线最小间隔大于2.5米

B、工作频率差的减小,天线的间距应加大

C、频率差和发射功率对天线的间距不具有决定性的作用

D、在同一频率差下,发射功率越大,产生临近频率相互干扰的可能性越大,因此应加大天线的间距

答案

参考答案:C

阅读理解

阅读理解。

     If you do not use your arms or your legs for some time, they become weak; when you start using them

again, they slowly become strong again. Everybody knows that. Yet many people do not seem to know that

memory works in the same way. When someone says that he has a good memory, he really means that he

keeps his memory in practice by using it. When someone else says that his memory is poor, he really means

that he does not give it enough chance to become strong. If a friend says that his arms and legs are weak, we

know that it is his own fault (过错). But if he tells us that he has a poor memory, many of us think that his

parents are to blame (受责备), and few of us know that it is just his own fault. Have you ever found that some

people can't read or write but usually they have better memories? This is because they cannot read or write and

they have to remember things; they cannot write down in a little notebook. They have to remember days,

names, songs and stories; so their memory is the whole time being exercised. So if you want to have a good

memory, learn from the people: Practice remembering.

1. The main reason why one is poor memory is that _______.

A. his father or mother may have a poor memory

B. He does not use his arms or legs for some time

C. his memory is not often used

D. he can't read or write

2. If you do not use your arms or legs for some time _______.

A. you can't use them any more

B. they become weak and won't become strong until you use them again.

C. they will become stronger

D. they will become neither stronger nor weaker

3. Which of the following is NOT true?

A. Your memory works in the same way as your arms or legs.

B. Your memory, like your arms or legs, becomes weak if you don't give it enough chance for practice.

C. A good memory comes from more practice.

D. Don't learn how to read and write if you want to have a better memory.

4. Some people can't read or write, but they usually have better memories, because _______.

A. they have saved much trouble

B. they have saved much time to remember things

C. they have to use their memories all the time

D. they can't write everything in a little notebook

5. Which is the best title for this passage?

A. Don't Stop Using Your Arms Or Legs

B. How to Have a Good Memory

C. Strong Arms and Good Memories

D. Learn From the People

单项选择题