閱讀理解
Some radio signals are reflected when they meet solid objects; for example, television signals are reflected when they meet walls and houses, or when they meet an aircraft in the sky. The picture is not clear when the signals are reflected like this. When a plane is flying near the house, the picture on the television screen sometimes dances about in a very troublesome (討厭的) way.
These reflections, which led Watt to the science of radar, are now used a great deal. Radar instruments (儀器) can show the direction and the distance of aircraft. The signals are reflected only when the instrument points at the aircraft; this shows the direction. How do we find the distance?
Electromagnetic (電磁的) waves travel at a speed of 186, 300 miles per second. We know when the signal is sent out; we notice when it comes back. The signal takes a small fraction (小部分) of a second to go and return, but this time is known. So we know the distance from the ground to the plane.
Radar is very important to ships on the sea. In most big ships, a radar instrument is always watching the sea on all sides. It transmits (發(fā)射) a beam [(光線的)束] of radar waves and turns round all the time. If any other ship reflects the signal, a white spot is shown on a screen on board.
Big aircraft also use radar. The instrument finds other aircraft in the sky. A man’s eye is not good enough to do this because it cannot see far enough, but the radar beam can see for many miles.
A big plane flies at about 600 miles per hour, which is ten miles per minute. If two jet planes are flying towards each other, they are twenty miles nearer together after a minute has passed. This is dangerous unless the pilots know the facts and the radar instruments show them the facts.
1.What is necessary for the reflection of a radio signal is the ________ of an object.
[ ]
2.It can be inferred that Watt got the idea of his invention of radar from ________.
[ ]
A.the science of radar
B.shooting stars
C.the reflection of a radio signal
D.none of these
3.By the use of radar we can know ________.
[ ]
A.the distance of a solid object far away
B.everything we want to see
C.the direction of a far-away object
D.Both A and C.
4.The speed of electromagnetic waves is ________.
[ ]
A.600 miles per second
B.more than 180 thousand miles per second
C.a(chǎn)bout 18 thousand miles per second
D.none of the above
5.When a radar instrumant spots something, we can see, according to the author, ________ on its screen.
[ ]
A.some electromagnetic waves
B.a(chǎn) beam of light
C.a(chǎn) white spot
D.some numbers
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科目:高中英語(yǔ) 來(lái)源:高中課程新學(xué)案 高中三年級(jí)、英語(yǔ) 題型:050
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科目:高中英語(yǔ) 來(lái)源:黃岡重點(diǎn)作業(yè) 高一英語(yǔ)(下) 題型:050
閱讀理解:
Meaningful Colours
Mary did not understand such sentences as “She is blue Today”, “You are yellow”,“He has a green thumb (大拇指)”,“He has told a little white lie”and so on. And she went to her teacher for help.
Mary : Mrs Smith, there is a colour in each of these sentences. What do they mean?
Mrs Smith : In everyday English, Mary, blue sometimes means sad. Yellowafraid. A person with a green thumbgrows plants well. And a white lie is not a bad one.
Mary : Would you give me an example for “a white lie”?
Mrs Smith: Certainly. Now I give you some cake. In fact you don't like it, but you won't say it. Instead, you say, “No, thanks. I'm not hungry.”That's a white lie.
Mary: Oh, I see. Thank you very much.
1.Sometimes “yellow”means “afraid” in ________ English.
[ ]
2.The farmer doesn't have a green thumb, that is to say ________.
[ ]
3.John is ________ go to out alone at night. He's yellow!
[ ]
4.Mary didn't want to tell me ________ of her serious illness.
[ ]She told me a white lie.
5.If you fail to pass the exams, you'll be ________.
[ ]
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科目:高中英語(yǔ) 來(lái)源:黃岡重點(diǎn)作業(yè) 高一英語(yǔ)(下) 題型:050
閱讀理解:
In the United States, boys and girls start school when they are five years old. In some states they must stay in school until they are sixteen. Most students are seventeen or eighteen years old when they graduate from secondary school. Another name for secondary school is high school.
Most children go to public elementary (初小) and secondary school. The parents of public school pupils do not have to pay directly (直接地) for their children's education because tax (稅)money supports the public schools. If a child attends a private (私立) school, his parents pay the school for the child's education.
Today about half of the high school graduates go on to colleges and universities. Some colleges and universities receive tax money from the governments. A student at a state university does not have to pay very much if his parents live in that state. Private colleges and universities are expensive. However, almost half of the colleges students in the United States work while they are studying. When a student's family isn't rich, he has to earn money for part of his college expenses.
1.In the United States, children can start school ________.
[ ]
2.________ between secondary school and high school.
[ ]
3.Most parents in the US ________ for their children's education.
[ ]
4.Some students at a state university don't have to pay much money for their higher education because ________.
[ ]
A.tax money supports some colleges and universities
B.their parents live in that state
C.they earn money
D.their family are not rich
5.Students from poor families ________.
[ ]
A.stop studying after secondary school
B.don't go on to colleges and universities
C.have to work to support their families
D.earn money for part of their college expenses
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科目:高中英語(yǔ) 來(lái)源:101網(wǎng)校同步練習(xí) 高二英語(yǔ) 人民教育出版社(新課標(biāo)A 2002-3年初審?fù)ㄟ^(guò)) 人教版 題型:050
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科目:高中英語(yǔ) 來(lái)源:101網(wǎng)校同步練習(xí) 高三英語(yǔ) 人民教育出版社(新課標(biāo)A 2002-3年初審) 人教版 題型:050
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