题干

为减少室温气体排放,人们积极寻找不含碳元素的燃料.研究发现氨气燃烧释放大量的能量,生成空气中含量最多的气体和一种氧化物,不产生污染,氨气燃烧的化学方程式为____.熄灭时,将导出氨气的导管关闭,利用的灭火原理是____.
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4NH3+3O2 \u70b9\u71c3_

同类题2

阅读下面短文,然后根据短文内容补表格中所缺失的信息,每空仅填一词。

    Every morning my father buys a newspaper on his way to work. Every day I open my books in class and start lessons. Every evening my mother looks through magazines at home. And every night, I look at the posters with photos of David Beckham and Yao Ming on my bedroom wall before I go to sleep. Can we imagine life without paper or print?

    Paper was first created about 2,000 years ago, and has been made from silk, cotton, bamboo, and, since the 19th century, from wood. People learned to write words on paper to make a book. But in those days, books could only be produced one at a time by hand. As a result, they were expensive and rare. And because there weren't many books, few people learned to read.

    Then printing was invented in China. The first printed books were made by putting ink on a wooden block and holding the paper against it. When printing was developed greatly at the beginning of the 11th century, books could be produced more quickly and cheaply. As a result, more people learned to read. After that, knowledge and ideas spread(传播) quickly, in a way that can be compared with the introduction of the Internet in the 20th century.

    But will books be needed in the future? Today information can be received online, downloaded from the Internet rather than found in books, and information can be kept on CD-ROMs or machines such as MP4 players. These machines are smaller and lighter than books so that they can be carried very easily.

    Computers are already used in classrooms, and newspapers and magazines can already be read online. So will books be replaced by computers one day? No, I don't think the Yao Ming poster on my bedroom wall will ever be replaced by a computer two metres high!

My family

Mother looks through____ at home in the evening.

There are posters of sports players on my bedroom wall.

2,000 years ago

Paper was made from silk, cotton and bamboo.

Books were expensive and rare because they were made by____

19th century

People made paper from ____.

Printing

Printing was China's great ____.

11th century

Printing was developed greatly.

Today

We receive information ____.

We keep information on MP4 players.

In the future

Books may (not) be replaced by computers.