📚 Year 7 CAIE Computing: Core Concepts Refresher | 七年级 CAIE 计算机：核心知识点梳理
Welcome to your Year 7 CAIE Computing revision guide. This article consolidates the essential knowledge you need to master for the Cambridge Lower Secondary programme, from digital safety and hardware to programming with Scratch and computational thinking. Read on to strengthen your understanding and boost your confidence.
欢迎来到七年级 CAIE 计算机复习指南。本文梳理了剑桥初中课程必须掌握的核心知识，涵盖数字安全、硬件、Scratch 编程和计算思维等内容。继续阅读，巩固理解，提升自信。
1. Digital Literacy and E-Safety | 数字素养与网络安全
Being digitally literate means you can use technology effectively and responsibly.
数字素养意味着你能有效且负责任地使用技术。
Always create strong passwords using a mix of letters, numbers, and symbols.
始终使用字母、数字和符号的组合创建强密码。
Never share personal information like your address or phone number with strangers online.
永远不要在网上与陌生人分享你的地址或电话号码等个人信息。
Think before you post — once something is online, it can be hard to remove completely.
发布前先思考——一旦内容上网，可能很难完全删除。
Cyberbullying is harmful behaviour online; always treat others with respect and report any abuse.
网络欺凌是网上的恶意行为；始终尊重他人并举报任何欺凌行为。
If you see something upsetting online, tell a trusted adult immediately.
如果你在网上看到令人不安的内容，立即告诉信任的成人。
2. Computer Hardware and Software | 计算机硬件与软件
Hardware refers to physical parts of a computer that you can touch, such as the monitor and keyboard.
硬件是指你可以触摸的计算机物理部件，如显示器和键盘。
Software consists of programs and applications that tell the hardware what to do.
软件由程序和应用程序组成，它们告诉硬件要做什么。
The Central Processing Unit (CPU) is like the ‘brain’ of the computer; it carries out instructions.
中央处理器（CPU）就像计算机的“大脑”；它执行指令。
RAM (Random Access Memory) temporarily stores data that the CPU needs quickly.
内存（随机存取存储器）临时存储 CPU 需要快速访问的数据。
Storage devices like hard drives keep your files and software even when the power is off.
像硬盘这样的存储设备在断电后仍能保存你的文件和软件。
Input devices send data to the computer; output devices show results.
输入设备向计算机发送数据；输出设备显示结果。
| Device | Description (EN) | 描述 (中文) |
|---|---|---|
| Keyboard | Enters text and commands | 输入文本和命令 |
| Mouse | Points, clicks, and selects items | 指向、点击和选择项目 |
| Monitor | Displays visual output | 显示视觉输出 |
| Printer | Produces physical copies of documents | 打印文档的纸质副本 |
| Hard Drive | Stores data permanently | 永久存储数据 |
3. Introduction to Algorithms | 算法初步
An algorithm is a sequence of well-defined instructions to solve a problem or complete a task.
算法是一系列明确定义的指令，用于解决问题或完成任务。
Algorithms can be described using everyday language, flowcharts, or pseudocode.
算法可以用日常语言、流程图或伪代码来描述。
A simple algorithm for brushing your teeth: Step 1: Wet toothbrush. Step 2: Apply toothpaste. Step 3: Brush all teeth for 2 minutes. Step 4: Rinse mouth.
刷牙的简单算法：步骤1：弄湿牙刷。步骤2：挤牙膏。步骤3：刷所有牙齿两分钟。步骤4：漱口。
In computing, algorithms must be precise and finite — they must have a clear end.
在计算中，算法必须精确且有限——必须有明确的结束。
Sequence is the most basic control structure: executing steps one after another.
顺序是最基本的控制结构：按顺序依次执行步骤。
Algorithms form the foundation of all computer programs.
算法构成所有计算机程序的基础。
4. Programming with Scratch | Scratch 编程基础
Scratch is a block-based programming language where you snap together code blocks to create interactive stories, games, and animations.
Scratch 是一种基于积木的编程语言，你可以拼接代码积木来创建交互式故事、游戏和动画。
The stage is where your sprites appear; sprites are characters or objects that perform actions.
舞台是角色出现的地方；角色是执行动作的人物或对象。
The ‘When green flag clicked’ block starts your program.
“当绿旗被点击”积木启动你的程序。
Motion blocks like ‘move 10 steps’ control a sprite’s movement.
“移动10步”这样的运动积木控制角色的移动。
You can use loops like ‘repeat 10’ to make actions happen multiple times.
你可以使用“重复10次”这样的循环来让动作多次发生。
Conditional statements such as ‘if touching edge?’ allow sprites to react to events.
条件语句如“如果碰到边缘？”让角色对事件做出反应。
Variables can store information like a score in a game.
变量可以存储信息，例如游戏中的分数。
Events, sensing blocks, and broadcasts help different sprites communicate.
事件、侦测积木和广播积木帮助不同的角色之间进行通信。
5. Data Representation: Binary and Bits | 数据表示：二进制与比特
Computers use binary, a number system with only two digits: 0 and 1.
计算机使用二进制，一种只有两个数字的系统：0 和 1。
A single binary digit is called a bit; 8 bits form a byte.
一个单独的二进制数字称为一个比特（位）；8 个比特组成一个字节。
Each position in a binary number represents a power of 2: 2³, 2², 2¹, 2⁰ (8, 4, 2, 1).
二进制数中的每个位置代表2的幂：2³、2²、2¹、2⁰（8、4、2、1）。
To convert binary 1011₂ to decimal: (1 × 8) + (0 × 4) + (1 × 2) + (1 × 1) = 11.
将二进制1011₂转换为十进制：(1 × 8) + (0 × 4) + (1 × 2) + (1 × 1) = 11。
Characters like ‘A’ are represented using ASCII codes, e.g., ‘A’ = 65 = 01000001 in binary.
像“A”这样的字符使用 ASCII 码表示，例如“A” = 65 = 二进制 01000001。
Larger units include kilobyte (KB = 1024 bytes), megabyte, gigabyte, and terabyte.
更大的单位包括千字节（KB = 1024 字节）、兆字节、吉字节和太字节。
Binary is the only language hardware understands directly.
二进制是硬件唯一直接理解的语言。
6. Networks and the Internet | 网络与互联网
A computer network is a group of connected devices that can share data and resources.
计算机网络是一组能够共享数据和资源的连接设备。
A Local Area Network (LAN) covers a small area like a school or home.
局域网（LAN）覆盖像学校或家庭这样的小区域。
A Wide Area Network (WAN) spans large geographical areas, with the Internet being the largest WAN.
广域网（WAN）跨越大的地理区域，互联网是最大的广域网。
A router directs data between different networks; a modem connects you to your Internet Service Provider.
路由器在不同网络之间引导数据；调制解调器将你连接到互联网服务提供商。
Web pages are accessed via a browser using URLs; a URL identifies the location of a webpage.
网页通过浏览器使用 URL 访问；URL 标识网页的位置。
Data is sent in small packets across the network, which are reassembled at the destination.
数据在网络上以小的数据包发送，然后在目的地重新组装。
Be cautious when using public Wi-Fi; avoid entering sensitive information.
使用公共 Wi-Fi 时要谨慎；避免输入敏感信息。
Networked devices also include printers, smartphones, and gaming consoles.
联网设备还包括打印机、智能手机和游戏机。
7. Computational Thinking | 计算思维
Computational thinking is a problem-solving approach involving decomposition, pattern recognition, abstraction, and algorithm design.
Published by TutorHao | Year 7 Computer Science Revision Series | aleveler.com
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