Question

The Eve of Radar

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　　1　“Did you know that radar is an acronym and a palindrome?” Pat asked Charlie on a long return flight from Europe.

　　2　“A pal in a dome?” Charlie exclaimed. “What are you talking about?”

　　3　“I’m talking about the word radar,” Pat explained. “It's a palindrome because the letters read the same forward and backward like mom, dad, and did. “It's an acronym because the letters stand for words.”

　　4　“Oh, radar stands for radio detecting and ranging,” Charlie laughed. “I do know that much. I also know that a radar set is made up of a transmitter and a receiver, and without it our jobs would be a lot harder.”

　　5　The transmitter that Charlie mentioned sends out radio waves. When these waves strike something, they bounce off it. Then they are picked up by the receiving part of the radar set. The speed and intensity of the returning radio waves tell how far away an object is. They also tell if it is moving and at what speed it is moving. Radar waves travel at the speed of light more than one hundred eighty-six thousand miles per second.

　　6　Pat and Charlie make good use of radar's ability to identify the weather situation. Often their visibility is dimmed by mist, fog, clouds, or storms. When this happens, they can turn to radar for help. The waves can see areas of heavy rain or snow inside clouds that otherwise look harmless.

　　7　Instead of looking through storms, radar can also be adjusted to track storms. Weather experts can use radar to see where a storm is and how bad it will get. They can often tell what the storm's path will be.

　　8　Radar helps planes avoid accidents, too. Radar waves work by hitting objects miles away. These objects are seen as blips of light on a plane's radar screen. Using radar in this way, Pat and Charlie can be warned of danger while it is still distant.

　　9　For their approach and landing instructions, Pat and Charlie rely on the airport control tower. People in the tower assign each plane a direction and a safe altitude for landing. In the control tower, radar screens show each plane in the vicinity. When visibility is poor, radar can be used to guide the landings.

　　10　Weather forecasting and flight assistance are not the only uses for radar. Astronomers use it to study other planets. Zoologists use it to study the flight patterns of birds.

　　11　Ships use radar, too. Radar can pinpoint dangers such as icebergs or rocks.

　　12　“So, the word radar is a palindrome and an acronym,” Charlie grinned. “I guess I learn something new every day. How did I ever get along without you, Pat?”

　　

Read to find out how radar is used.

Write the words from the story that has the meanings below.

　　1.ability to see ________ （Par. 6)

　　2.people who study animals _______________ （Par. 10)

Answer the following question.

　3.What two sections does a radar set have? ________________________

 

Answer 1

答案：
解析：

1.　　   见第六段第一句话； 2.　　   Zoologists的意思就是people who study animals； 3.　　   见第四段。

提示：

1.　　   the weather situation 2.　　   use a radar to study the flight patterns of birds 3.　　   a transmitter and a receiver