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　　根据短文内容，从下面的选项中选出能填入空白处的最佳选项。（其中两项多余）

　　On March 21, 2022,a China Eastern Airlines plane with 132 people aboard crashed(撞毁)in

　　Guangxi. It dropped from 8,869 meters to1,333.5 meters in just three minutes. 1 That brought the hope of understanding what caused the country's worst airline disaster(灾难）in years.

　　However,what are black boxes? A black box is also known as the flight recorder.Every plane has at least two black boxes. 2 They record everything about a flight such as its speed， altitude(高度)，conversations, and air pressure among other things. The information helps to discover what lead to an accident and prevent similar accidents in the future.

　　The use of black boxes dates back to the early 1950s. It's said an Australian scientist named Dr David Warren made the invention.He realized that people who can best explain what happened are unluckily dead. 3

　　Despite its name, a black box is neither black in color, nor looks like a box. Though called a black box,it is painted in bright orange color. 4 It is not certain how it got its name.

　　Each box weighs about 4.5 kg. They are generally made out of special materials. 5 To make black boxes easier to discover under water,they can let out signals(信号) for 30days.

　　A. Most planes didn't have them at first. B.This helps them survive(生存)from heat, cold or wetness.

　　C. Usually. one is in the front and the other is in the back.

　　D. They have tried their best to look for the people aboard.

　　E. Then the idea of a voice recorder to be present in flights was born.

　　F. After days of searching,its two black boxes were finally found.

　　G. So the people looking for it can have the best chance to find it.

　　1._________   2._________   3._________   4._________   5._________

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