1. A 400-word composition for primary school students describing computers. There is an exquisite computer in my small room, which my parents bought for me to study during the summer vacation.

My computer is silver-white, and the mainframe is flat and sturdy.

The display has bright colors and clear images, and I also equipped it with two small "ears" - speakers.

Even my brother, who always thought his computer was the best, became more and more envious of me.

I can't put down this computer.

Whenever I open "windows", I can't wait to explore the infinite knowledge and mysteries inside. I feel like I am swimming in the ocean of knowledge, which makes me beautiful.

I remember one time, I was online again at noon. Lunch was already prepared, and my mother called me to eat, but I was too interested in the computer, so I didn’t hear it. Then my mother called again... Finally, my mother got angry.

He walked up to me and shouted to me: "Li Zhe, hurry up and eat. Do you want to try my 'tightening curse'?" I had to turn off my phone after hearing this.

But I was still thinking about an essay on the Internet, so I walked into the dining room leisurely.

At this time, I only heard the laughter of "Haha..." and I recovered. It turned out that I had walked to the bedroom.

My face suddenly turned red.

Even now I laugh when I think about it.

It seems that it is not an exaggeration to say that the computer is an ocean of knowledge and an invisible teacher.

2. Use computer explanation method to write an essay. When it comes to computers, I believe everyone is very familiar with them.

Computers are also called electronic computers.

Nowadays, with the development of science and technology, computers have entered thousands of households.

Computers are generally divided into two categories; one is personal computers, which include desktops, laptops, and the latest model is tablets.

The other type is supercomputers, which have a computing speed of more than 100 million operations per second and are mainly used in banking, scientific research, military, etc.

Computers are composed of hardware systems and software systems.

The computer hardware system mainly consists of a host, a monitor, a keyboard, a mouse, a speaker, a camera, etc.

The host is the supervisor of the computer, just like our brain, controlling the computer's daily work.

The monitor is like our eyes, showing us the results of all work.

There are 26 English letter keys, direction keys, numeric keys and several important keys on the keyboard. It is the main input device of the computer.

The mouse is like a mouse on the table, but it is very useful and can flexibly command various applications.

Speakers can lead us into the wonderful world of music.

Cameras allow us to communicate with people around the world without leaving home.

Computer software systems are divided into two categories; one is operating system software, which mainly includes Windows operating system and Linux operating system, and the most primitive is DOS operating system.

They are the underlying system software of the computer, responsible for managing, scheduling, and directing the computer's software and hardware resources to coordinate their work. Without it, no computer can operate normally.

It acts as a middleman between resource users and resources. For example, when a user (or program) saves a file to disk, the operating system will start to work: manage the allocation of disk space, and transfer the information to be saved from the memory.

Write to disk etc.

When a user wants to run a program, the operating system must first load the program into memory. When the program is executed, the operating system will let the program use the CPU.

The other type is application software, which can be used for office work, games, and security.

Computers have many uses: they can surf the Internet, such as chatting, sending emails, listening to music, playing games, logging into QQ, checking information, etc.; they can manage data, for example, the computers in the school library are used to register the borrowing of books; they can

Accounting, such as computers in supermarkets, are used for accounting; they can also be used to control production, such as computers in cement factories that can automatically control production.

Look, computers are really capable in all aspects!

Computers are closely related to people's lives and make people's lives better.

3. A 500-word explanatory essay describing the computer. Computers, which were regarded as mysterious by the Chinese a few decades ago, have gradually unveiled their hazy veil and entered the homes of Chinese people.

Computer is another name for computer.

Because of this, people often associate it with addition, subtraction, multiplication and division, which makes students like us who have studied hard for sixteen or seven years full of expectations for it.

When I was in elementary school, computers used pen arithmetic. When I was in middle school, I learned abacus and reached the highest level of "seeing a few numbers without dividing by nine." After I went to college, it was clear that pen arithmetic and abacus calculations could not keep up with the speed of calculation, so I had to use abacus calculations with poor accuracy.

logarithmic slide rule.

Participants were asked to perform calculations with high precision, and a hand-operated computer was used for multiplication and division calculations.

This kind of hand-cranked calculator lived up to its name and was specially used for "calculations" of multiplication and division.

Although it was noisy to use and was far slower than the calculators that are widely used today, it was a rare "treasure" at the time.