A little airplane has given new meaning to the term "going hyper."
The Hyper-X recently broke the record for air-breathing jet planes when it traveled at a hypersonic speed of seven times the speed of sound. That’s about 5,000 miles per hour. At this speed, you’d get around the world -- flying along the equator -- in less than 5 hours.
The Hyper-X is an unmanned, experimental aircraft just 12 feet long. It achieves hypersonic speed using a special sort of engine known as a scramjet. It may sound like something from a comic book, but engineers have been experimenting with scramjets since the 1960s.
For an engine to burn fuel and produce energy, it needs oxygen. A jet engine, like those on passenger airplanes, gets oxygen from the air. A rocket engine typically goes faster but has to carry its own supply of oxygen. A scramjet engine goes as fast as a rocket, but it doesn’t have to carry its own oxygen
A. it was the first air-breathing jet plane
B. it flew along the equator
C. it flew at speeds smaller than five times the speed of sound
D. it traveled at a supersonic speed

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[多选题]灭火的基本方法除拨打“119”火警电话报警外，还有（）方法。
A.冷却灭火法
B.隔离灭火法
C.窒息灭火法
D.化学抑制灭火法

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[单选题]JWJXC-7200型继电器的鉴别销号码为（）
A.14、55
B.15、55
C.12、55
D.14、54

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[多项选择]常见的互换类型有（）。
A. 权益互换
B. 货币互换
C. 远期互换
D. 利率互换

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[单选题]下列哪一项关于选区划分的说法不正确？
A.选区可以按居住状况划分
B.选区可以按生产单位、事业单位、工作单位划分
C.本行政区域内各选区每一代表所代表的人口数应当大体相等
D.选区的大小，按照每一选区选一名至五名代表划分

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[简答题]

a) To ask for and give a reply to an inquiry, offer, order, or complaint.
b) To keep a record of all the important facts for ready reference. The language of old - style business letters is reader. A confused and over long letter may be put aside until someone explains its meaning, and this may mean delays. Since a letter is written for the reader, the language of modern business letters is simple, clear and direct. The writer states the purpose of his letter briefly, and the letter is short and friendly. Such letters help the writer as much as the reader, and will probably mean an earlier reply.
Here are two letters. One is about an inquiry and tile other is the reply to it. Both of them are simple and clear.
A Letter of Inquiry
August 10th, 1999
Dear Sirs,
One of our customers is interested in your bicycles, particularly Model No. PA - 18.
Please send us a copy of your illustrated catalogue, quoting your prices FOB

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[多选题]关于离心通风机叶型的说法正确的是( )。
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