📚 Core Knowledge Summary for Year 7 WJEC Computer Science | Year 7 WJEC 计算机：核心知识点梳理
Welcome to your Year 7 WJEC Computer Science journey! This guide brings together all the essential topics you will encounter in your first year of secondary computing. We will explore what makes a computer tick, how data is represented and processed, the basics of networks and the internet, and the core problem‑solving skills that form the foundation of programming. Whether you are revising for an end‑of‑year test or simply curious about how technology works, this article will give you a clear, bilingual summary of the key ideas.
欢迎开启 Year 7 WJEC 计算机科学的学习之旅！本篇指南汇总了中学第一年你将接触到的所有核心主题。我们将一起探索计算机的运作原理、数据的表示与处理方式、网络和互联网的基础知识，以及构成程序设计根基的核心问题解决能力。无论你是在为年终考试复习，还是单纯对技术如何运作感到好奇，这篇文章都会为你提供一份清晰的双语要点总结。
1. What is a Computer? | 什么是计算机？
A computer is an electronic device that takes in data (input), processes it according to a set of instructions (a program), and produces a result (output). At its heart, a computer follows the IPO model: Input – Process – Output. Computers can be found in many forms, from desktops and laptops to smartphones, games consoles, and even embedded systems inside cars and washing machines.
计算机是一种电子设备，它接收数据（输入），按照一套指令（程序）进行处理，并产生结果（输出）。计算机的核心遵循 IPO 模式：输入 – 处理 – 输出。计算机有多种形态，从台式机、笔记本电脑到智能手机、游戏主机，甚至汽车和洗衣机内部的嵌入式系统，都属于计算机。
- Input – data or commands fed into the computer (e.g. typing on a keyboard). / 输入 – 送入计算机的数据或指令（如用键盘打字）。
- Process – the computer manipulates the data using its processor. / 处理 – 计算机用其处理器对数据进行操作。
- Output – the result displayed or produced (e.g. text on a screen). / 输出 – 显示或产生的结果（如屏幕上的文字）。
Modern computers are general‑purpose machines, meaning they can be programmed to carry out many different tasks. This flexibility is what makes them so powerful.
现代计算机是通用机器，这意味着它们可以通过编程来执行许多不同的任务。这种灵活性正是它们如此强大的原因所在。
2. Hardware and Software | 硬件与软件
Every computer system consists of two main parts: hardware and software. Hardware refers to the physical components you can touch, such as the monitor, keyboard, motherboard, and hard drive. Software is the collection of programs and instructions that tell the hardware what to do.
每个计算机系统都由两个主要部分组成：硬件和软件。硬件指的是你可以触摸到的物理组件，如显示器、键盘、主板和硬盘。软件则是告诉硬件做什么的程序和指令的集合。
There are two main types of software: system software and application software. System software includes the operating system (like Windows, macOS, or Linux), which manages the computer's resources and allows you to interact with the machine. It also includes utility programs that help maintain the computer. Application software is designed to help the user perform specific tasks, for example word processors, web browsers, and games.
软件主要有两种类型：系统软件和应用软件。系统软件包括操作系统（如 Windows、macOS 或 Linux），它管理计算机的资源，并允许你与机器交互。它还包括用于维护计算机的实用程序。应用软件旨在帮助用户执行特定任务，例如文字处理软件、网页浏览器和游戏。
Without hardware, software has nothing to run on; without software, hardware does not know what to do. Both are equally important.
没有硬件，软件就没有运行的基础；没有软件，硬件就不知道要做什么。两者同等重要。
3. Input and Output Devices | 输入与输出设备
Input devices send data and control signals to a computer. Common input devices include the keyboard, mouse, touchscreen, microphone, scanner, and webcam. Sensors (such as temperature or light sensors) are also input devices, often used in control systems.
输入设备将数据和控制信号发送给计算机。常见的输入设备包括键盘、鼠标、触摸屏、麦克风、扫描仪和网络摄像头。传感器（如温度传感器或光传感器）也是输入设备，常用于控制系统。
Output devices receive data from the computer and present it to the user. The most obvious output device is the monitor (or screen), which displays visual information. Other output devices are printers, speakers, and headphones. Actuators, like motors or buzzers, are output devices that can produce movement or sound in response to computer commands.
输出设备从计算机接收数据，并将其呈现给用户。最明显的输出设备是显示器（或屏幕），它显示视觉信息。其他输出设备包括打印机、扬声器和耳机。执行器，如电机或蜂鸣器，是输出设备，可以根据计算机指令产生动作或声音。
Some devices can act as both input and output – for example, a touchscreen displays information (output) and detects touch (input).
有些设备可以同时充当输入和输出设备——例如，触摸屏既能显示信息（输出），又能检测触摸（输入）。
4. The Central Processing Unit (CPU) | 中央处理器 (CPU)
The CPU is often called the 'brain' of the computer. It carries out all the processing of data by following the instructions in programs. The CPU performs a cycle called the fetch‑decode‑execute cycle. It fetches an instruction from memory, decodes it to understand what needs to be done, and then executes (carries out) that instruction. This cycle repeats billions of times per second.
CPU 通常被称为计算机的“大脑”。它按照程序中的指令执行所有的数据处理工作。CPU 执行一个叫做取指－解码－执行的周期。它从内存中取出指令，解码以明白要做什么，然后执行（实施）该指令。这个周期每秒重复数十亿次。
The speed of a CPU is measured in hertz (Hz). Modern processors run at several gigahertz (GHz), meaning billions of cycles per second. CPUs can have multiple cores, which allow them to process several instructions simultaneously, making the computer faster at multitasking.
CPU 的速度以赫兹 (Hz) 为单位进行测量。现代处理器的运行频率可达数吉赫兹 (GHz)，即每秒数十亿个周期。CPU 可以有多个核心，这使它们能够同时处理多条指令，让计算机在多任务处理时更快。
Two main companies design the CPUs found in most devices: Intel and AMD. However, a newer architecture called ARM is used in nearly all smartphones because it is very power‑efficient.
有两家主要的公司设计了大多数设备中的 CPU：英特尔和 AMD。然而，一种称为 ARM 的新型架构被用于几乎所有智能手机，因为它非常节能。
5. Memory and Storage | 内存与存储
Memory and storage are both used to hold data, but they serve different purposes. RAM (Random Access Memory) is the computer's short‑term, working memory. It holds the data and programs that are currently in use. RAM is volatile, which means it loses all its contents when the power is turned off.
内存和存储都用于保存数据，但它们的功能不同。RAM（随机存取存储器）是计算机的短期工作内存。它保存当前正在使用的数据和程序。RAM 是易失性的，这意味着当电源关闭时，其中的所有内容都会丢失。
Storage (also called secondary storage) is non‑volatile, meaning it retains data even without power. Common types of storage include the hard disk drive (HDD) which uses magnetic platters, and the solid‑state drive (SSD) which uses flash memory and has no moving parts. SSDs are much faster and more durable but usually more expensive per gigabyte than HDDs. USB flash drives, SD cards, and optical discs (CDs, DVDs) are other forms of storage.
存储器（也叫辅助存储器）是非易失性的，这意味着即使没有电源，它也能保存数据。常见的存储类型包括使用磁性盘片的硬盘驱动器 (HDD) 和使用闪存、没有活动部件的固态驱动器 (SSD)。SSD 速度更快、更耐用，但通常每 GB 的价格比 HDD 更高。U 盘、SD 卡和光盘（CD、DVD）都是其他形式的存储器。
Another important type of memory is ROM (Read Only Memory). It holds the firmware – the essential instructions needed to start up the computer, called the BIOS or UEFI. ROM is non‑volatile and, as its name suggests, is normally only read from, not written to by the user.
另一种重要的内存是ROM（只读存储器）。它保存着固件——启动计算机所必需的指令，称为 BIOS 或 UEFI。ROM 是非易失性的，而且顾名思义，用户通常只能从中读取数据，而不能写入。
6. Binary and Data Representation | 二进制与数据表示
Computers do not understand human languages; they use binary – a number system made up of only two digits: 0 and 1. Each 0 or 1 is called a bit. A group of 8 bits makes a byte. Everything inside a computer, from numbers and letters to pictures and sound, is represented using patterns of bits.
计算机不懂人类语言；它们使用二进制——一种仅由 0 和 1 两个数字组成的数制。每个 0 或 1 被称为一个比特。8 个比特组成一个字节。计算机内部的一切，从数字、字母到图片和声音，都是用比特的组合模式来表示的。
To convert a binary number to decimal (denary), you can use place values. For an 8‑ 1 translates to: 0×128 + 1×64 + 0×32 + 0×16 + 1×8 + 1×4 + 0×2 + 1×1 = 64 + 8 + 4 + 1 = 77.
要将二进制数转换为十进制（我们日常使用的数制），你可以使用位权值。对于一个 8 位字节，其列值分别为 128, 64, 32, 16, 8, 4, 2, 1。例如，二进制数 01001101 转换为十进制是：0×128 + 1×64 + 0×32 + 0×16 + 1×8 + 1×4 + 0×2 + 1×1 = 64 + 8 + 4 + 1 = 77。
Text can be represented using character codes like ASCII (American Standard Code for Information Interchange) which uses 7 bits to represent 128 characters, or Unicode which can represent characters from all major world languages and uses up to 32 bits per character. Images are often stored as a grid of pixels, with each pixel's colour represented by binary numbers. Sound is sampled many thousand times per second and each sample is turned into a binary value.
文本可以使用字符编码来表示，比如 ASCII（美国信息交换标准码），它用 7 个比特表示 128 个字符；或者 Unicode，它能表示世界上所有主要语言的字符，每个字符最多使用 32 个比特。图像通常以像素网格的形式存储，每个像素的颜色用二进制数表示。声音则被以每秒数千次的频率采样，每个采样都转化为二进制值。
in binary terms, 1 KiB = 2¹⁰ bytes = 1024 bytes, but for GCSE and everyday use, 1000 is acceptable.)
存储容量遵循一定的模式：1 千字节 (KB) ≈ 1000 字节，1 兆字节 (MB) ≈ 1000 KB，1 吉字节 (GB) ≈ 1000 MB，1 太字节 (TB) ≈ 1000 GB。（严格从二进制角度讲，1 KiB = 2¹⁰ 字节 = 1024 字节，但在 GCSE 和日常使用中，1000 是可以接受的。）
7. Computer Networks | 计算机网络
A network is formed when two or more computers are connected together so they can share resources and communicate. Networks can be wired (using cables such as Ethernet) or wireless (using Wi‑Fi or Bluetooth). The main advantages of networking include sharing files, sharing hardware like printers, and enabling communication (e.g. email, instant messaging).
当两台或更多计算机连接在一起，以便共享资源和通信时，就形成了一个网络。网络可以是有线的（使用以太网等电缆），也可以是无线的（使用 Wi‑Fi 或蓝牙）。网络的主要优点包括共享文件、共享打印机等硬件，以及实现通信（如电子邮件、即时消息）。
Networks are often classified by their size. A LAN (Local Area Network) covers a small geographical area, like a school or an office. A WAN (Wide Area Network) connects LANs over large distances; the internet is the largest WAN. The hardware used to build a network includes a switch that connects devices together within a LAN, a router that connects different networks and directs data traffic, and a network interface card (NIC) in each device.
网络通常根据规模进行分类。LAN（局域网）覆盖较小的地理区域，如一所学校或一间办公室。WAN（广域网）将相隔远距离的局域网连接起来；互联网是最大的广域网。用于构建网络的硬件包括：将局域网内设备连接在一起的交换机、连接不同网络并指挥数据流量的路由器，以及每台设备中的网络接口卡 (NIC)。
Data is sent across networks in small chunks called packets. Each packet contains the sender's and receiver's address, a piece of the actual data, and error‑checking information. Packets may take different routes and are reassembled at the destination.
数据以被称为数据包的小块形式在网络上传输。每个数据包都包含发送者和接收者的地址、一部分实际数据以及错误校验信息。数据包可能经过不同的路由，最后在目的地被重新组装起来。
8. The Internet and World Wide Web | 互联网与万维网
Many people use the terms 'internet' and 'World Wide Web' interchangeably, but they are not the same. The internet is a global network of computers and other devices connected together using communication protocols. The World Wide Web (WWW or simply the web) is a collection of web pages and other resources that are accessed using the internet. The web runs on top of the internet.
许多人将“互联网”和“万维网”这两个术语混用，但它们并不相同。互联网是一个全球性的计算机网络，通过通信协议将计算机和其他设备连接在一起。万维网（WWW，或简称网络）是可以通过互联网访问的网页和其他资源的集合。网络运行在互联网之上。
Web pages are written in a language called HTML (HyperText Markup Language). To view a web page, you need a web browser (such as Google Chrome, Microsoft Edge, or Safari). The browser sends a request to a web server where the page is stored, and the server returns the HTML file, which the browser then displays.
网页是用一种叫做 HTML（超文本标记语言）的语言编写的。要查看网页，你需要一个网页浏览器（如 Google Chrome、Microsoft Edge 或 Safari）。浏览器向存储页面的网络服务器发送请求，服务器返回 HTML 文件，然后由浏览器进行显示。
Every device on the internet has a unique numerical address called an IP address (Internet Protocol address). Because numbers are hard for humans to remember, we use domain names, like aleveler.com. The DNS (Domain Name System) translates domain names into IP addresses so that data can find its destination.
互联网上的每台设备都有一个独一无二的数字地址，称为 IP 地址（互联网协议地址）。由于数字不易被人类记住，我们使用域名，例如 aleveler.com。DNS（域名系统）将域名转换为 IP 地址，以便数据能够找到目的地。
9. Safety and Security Online | 在线安全与防护
Staying safe online is a vital skill. You should never share personal information (such as your full name, address, phone number, or school) with strangers online. Use strong, unique passwords for each account and never share them with anyone except a trusted adult. A strong password usually contains a mix of uppercase and lowercase letters, numbers, and symbols, and is at least 8 characters long.
保持上网安全是一项至关重要的技能。你绝不应该在网上与陌生人分享个人信息（如你的全名、住址、电话号码或学校）。为每个账户使用强大且唯一的密码，并且除了可信任的成年人外，不要与任何人分享。一个强密码通常包含大小写字母、数字和符号的混合，并且长度至少为 8 个字符。
Malware (malicious software) is a broad term for any program designed to harm a computer or steal data. Common types include viruses (which attach themselves to other files and spread), worms (which can copy themselves without a host file), and trojans (which disguise themselves as useful software). To protect against malware, you should keep your operating system and software up to date, use antivirus software, and avoid clicking on suspicious links or downloading attachments from unknown senders.
恶意软件是一个宽泛的术语，指任何旨在损害计算机或窃取数据的程序。常见的类型包括病毒（会附着在其他文件上并传播）、蠕虫（无需宿主文件即可自我复制）和特洛伊木马（将自己伪装成有用的软件）。为防范恶意软件，你应该保持操作系统和软件为最新版本，使用反病毒软件，并避免点击可疑链接或从未知发件人下载附件。
Phishing is a common trick used by criminals. They send fake emails or messages that look as if they come from a real company (like a bank or a game site) to trick you into giving away your login details. Always check the sender's email address carefully and never enter personal details on a site unless you are sure it is legitimate.
钓鱼是犯罪分子常用的伎俩。他们发送伪造的电子邮件或消息，看起来像是来自真实公司（如银行或游戏网站），目的是诱骗你泄露登录信息。务必仔细检查发件人的电子邮件地址，并且除非你确定网站是合法的，否则绝不在网站中输入个人信息。
Remember that once something is posted online, it can be very difficult to remove completely. Always think before you post – be respectful and protect your digital footprint.
请记住，一旦某些内容被发布到网上，就很难完全删除。发布前一定要三思——保持尊重，并保护好你的数字足迹。
10. Introduction to Algorithms | 算法简介
An algorithm is a step‑by‑step set of instructions designed to solve a problem or complete a task. Algorithms are everywhere: a recipe is like an algorithm for cooking, and the instructions to build a model are an algorithm. In computing, algorithms are written in a way that a computer can follow and execute.
算法是一组为解决某个问题或完成某项任务而设计的、逐步执行的指令。算法无处不在：一份食谱就像是烹饪的算法，搭建模型的说明书也是一种算法。在计算机领域，算法以一种计算机能够遵循和执行的方式编写。
Algorithms can be represented in different ways. Pseudocode is a simplified, human‑readable language that describes what the program should do, without worrying about strict programming syntax. Flowcharts use symbols to show the steps and the flow of control. The main symbols are: an oval for start/end, a rectangle for a process or action, a parallelogram for input/output, and a diamond for a decision (a question with a yes/no answer). Arrows show the direction of flow.
算法可以用不同的方式表示。伪代码是一种简化的、人类可读的语言，它描述程序应该做什么，而不必担心严格的编程语法。流程图使用符号来展示步骤和控制流。主要符号有：椭圆形表示开始/结束，矩形表示一个过程或操作，平行四边形表示输入/输出，菱形表示判断（一个有是/否答案的问题）。箭头指示流程的方向。
Three basic building blocks of algorithms are sequence (doing steps one after another), selection (making a choice, e.g. IF…THEN…ELSE), and iteration (repeating a block of code, e.g. using loops). Understanding these helps you design efficient algorithms.
算法的三个基本构建块是顺序（一个接一个地执行步骤）、选择（做出选择，例如 IF…THEN…ELSE）和迭代（重复一段代码，例如使用循环）。理解这些能帮助你设计高效的算法。
11. Programming Concepts | 编程概念
In Year 7, you are likely to be introduced to a visual programming language like Scratch or a text‑based language such as Python. Programming involves writing instructions that a computer can carry out. A variable is a named location in memory that stores a value, like a score in a game or a user's name. The value can change while the program is running.
在 Year 7，你很可能会接触到像 Scratch 这样的可视化编程语言，或者像 Python 这样的文本编程语言。编程就是编写计算机可以执行的指令。变量是内存中一个有名字的存储位置，用来保存一个值，比如游戏中的得分或用户的姓名。这个值在程序运行过程中可以改变。
Using selection with IF statements allows a program to react to different conditions. For example, IF the answer is correct THEN display 'Well done!' ELSE display 'Try again.'. An IF statement always evaluates a condition that is either true or false.
在 IF 语句中使用选择结构可以让程序对不同的情况作出反应。例如，IF 答案正确 THEN 显示“做得好！” ELSE 显示“再试一次。”。IF 语句始终对一个要么为真要么为假的条件进行判断。
Iteration (loops) saves time by repeating code. In Scratch, you might use a forever block or a repeat block. In Python, the while loop repeats as long as a condition remains true, and the for loop repeats a set number of times or over items in a list.
迭代（循环）通过重复执行代码来节省时间。在 Scratch 中，你可能会使用 forever 积木块或 repeat 积木块。在 Python 中，while 循环只要条件为真就一直重复执行，而 for 循环则重复执行设定的次数，或者遍历列表中的项目。
| Concept / 概念 | Scratch Example / Scratch 示例 | Python Example / Python 示例 |
|---|---|---|
| Variable / 变量 | set score to 0 |
score = 0 |
| Selection / 选择 | if touching colour? then |
if answer == 'yes': print('Correct') |
| Iteration / 迭代 | repeat 10 |
for i in range(10): print(i) |
Another important concept is debugging – finding and fixing errors in your code. These errors might be syntax errors (the code does not follow the rules of the language) or logic errors (the code runs but does not do what you intended). Reading error messages carefully and testing your code step by step are key debugging skills.
另一个重要的概念是调试——查找并修复代码中的错误。这些错误可能是语法错误（代码没有遵循语言的规则），也可能是逻辑错误（代码虽然能运行，但没有按你的意图执行）。仔细阅读错误信息，并逐步测试你的代码，是关键的调试技能。
12. Computational Thinking | 计算思维
Computational thinking is a set of problem‑solving skills that help you tackle complex problems in a structured way. It is not just for programmers – it can be used in any subject or everyday situation. The four key techniques are: decomposition, pattern recognition, abstraction, and algorithmic thinking.
计算思维是一套问题解决技能，能帮助你以结构化的方式处理复杂问题。它不仅适用于编程人员——还可以用于任何学科或日常情境。四项关键技术是：分解、模式识别、抽象和算法思维。
- Decomposition – breaking a large problem into smaller, more manageable parts. For example, planning a school event can be split into booking the venue, arranging food, sending invitations, and so on. / 分解——将一个大问题拆分成更小、更易处理的部分。例如，策划一次学校活动可以拆分为预订场地、安排餐饮、发送邀请函等。
- Pattern recognition – looking for similarities among problems or within a problem. If you have solved a similar problem before, you can reuse some of the same solutions. / 模式识别——在问题之间或问题内部寻找相似之处。如果你之前解决过类似的问题，就可以重用其中部分相同的解决方案。
- Abstraction – focusing on the important details and ignoring unnecessary information. When drawing a map for a friend, you would only include the roads and landmarks they need, not every single tree. / 抽象——关注重要细节，忽略无关信息。比如，在为朋友画地图时，你只需画出他们需要的道路和地标，而不是每一棵树。
- Algorithmic thinking – developing a step‑by‑step solution, or algorithm, that can be followed to reach the goal. / 算法思维——制定一个可以遵循的、逐步进行的解决方案或算法，以实现目标。
These techniques work together. You decompose a problem, recognise patterns, filter out irrelevant details through abstraction, and then design an algorithm. As you gain experience, you will start using these habits of mind automatically whenever you face a challenge.
这些技巧协同运作。你分解问题，识别模式，通过抽象过滤掉不相关的细节，然后设计算法。随着经验的积累，每当你面对挑战时，你会自然而然地开始运用这些思维习惯。
By mastering these core topics, you will build a strong foundation not only for the rest of your computer science studies at school but also for understanding the technology‑driven world around you. Keep experimenting, keep questioning, and enjoy the journey!
掌握了这些核心主题，你不仅能为今后学校里的计算机科学学习打下坚实的基础，也能更好地理解这个由技术驱动的周遭世界。持续尝试，不断提问，享受这段旅程吧！
Published by TutorHao | Computer Science Revision Series | aleveler.com
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