📚 IGCSE Edexcel Science: Command Words Decoded | IGCSE Edexcel 科学：指令词全解析
In IGCSE Edexcel Science, every question begins with a command word such as ‘describe’, ‘explain’ or ‘suggest’. These words tell you exactly what kind of response the examiner expects. Understanding them is just as important as knowing the science content itself.
在 IGCSE Edexcel 科学考试中，每道题都以 ‘describe’、’explain’ 或 ‘suggest’ 这样的指令词开头。这些词明确告诉考生考官期待什么类型的回答。理解它们与掌握科学知识本身同样重要。
1. What Are Command Words? | 什么是指令词？
Command words are standardised instructional verbs used by examining boards to signal the depth and type of answer required. In Edexcel IGCSE Science, marks are awarded for matching your response to the command word, not just for scientific facts.
指令词是考试局用来提示答案深度和类型的标准化动词。在 Edexcel IGCSE 科学考试中，分数不仅取决于科学事实，还取决于你的回答是否契合指令词。
A ‘state’ question may need only a single word or a short phrase, while an ‘evaluate’ question asks for a balanced judgement with evidence. If you treat all questions the same way, you will lose marks even when you know the material.
‘state’ 题可能只需要一个单词或短语，而 ‘evaluate’ 题则要求有证据支撑的平衡判断。如果你用同一种方式回答所有题目，就算掌握了知识点，也会丢分。
2. Common Command Words in Edexcel IGCSE Science | Edexcel IGCSE 科学中的常见指令词
Edexcel publishes a formal command word list for its science qualifications. The most frequent ones include: state, give, name, describe, explain, suggest, predict, calculate, compare, evaluate, outline, identify, deduce and determine.
Edexcel 官方公布了科学科目的指令词列表。最常出现的包括：state、give、name、describe、explain、suggest、predict、calculate、compare、evaluate、outline、identify、deduce 和 determine。
| Command Word | Level of Demand | Typical Mark Range |
| State / Give / Name | Low | 1–2 |
| Describe / Outline | Medium | 2–4 |
| Explain / Suggest | Medium–High | 3–6 |
| Compare / Evaluate | High | 4–6 |
3. Describe vs Explain | Describe 与 Explain 的区别
‘Describe’ asks you to say what happens, what you see, or what a pattern is. It is about observations and factual statements. For example: ‘Describe the effect of increasing temperature on enzyme activity.’ A correct answer might say that the rate of reaction increases up to the optimum temperature, then decreases rapidly.
‘describe’ 要求你说明发生了什么、看到了什么或规律是什么，重点是观察和事实陈述。例如：’Describe the effect of increasing temperature on enzyme activity.’ 正确答案可以说：反应速率在最适温度前随温度升高而加快，超过最适温度后迅速下降。
‘Explain’ goes one step further. It asks you to give reasons or mechanisms. Using the same enzyme example, an explanation must state that heat increases kinetic energy, leading to more successful collisions, until the enzyme denatures and the active site changes shape.
‘explain’ 更进一步，需要给出原因或机制。同样的酶活性例子，解释必须提到热能增加动能、导致更多有效碰撞，直到酶变性、活性位点形状改变。
In exams, ‘describe’ marks are usually gained by reading data or recalling observations. ‘Explain’ marks are gained by linking cause and effect. Always ask yourself: ‘Is this observation or reason?’
在考试中，’describe’ 的分数通常来自读取数据或回忆观察结果，而 ‘explain’ 的分数来自将原因与结果联系起来。做题时一定要问自己：’这是观察，还是理由？’
4. State, Give, Name | State、Give、Name
These three command words are the easiest, but they still trap many students. ‘State’ means a concise factual answer with no explanation. If a question says ‘State one factor that affects the rate of diffusion’, writing ‘temperature’ is enough.
这三个指令词最简单，但仍然会让很多学生失分。’state’ 意思是简明扼要的事实性答案，不需要解释。如果题目说 ‘State one factor that affects the rate of diffusion’，写 ‘temperature’ 就够了。
‘Give’ is almost identical to ‘state’, but it sometimes allows a little more flexibility. ‘Give one piece of evidence for the Big Bang theory’ could be answered with ‘cosmic microwave background radiation’.
‘give’ 与 ‘state’ 几乎相同，但有时允许稍微灵活一些。’Give one piece of evidence for the Big Bang theory’ 可以回答 ‘cosmic microwave background radiation’。
‘Name’ requires you to write the correct scientific term. It often refers to structures, organisms, apparatus or compounds. A common error is to describe the thing instead of naming it. For example, ‘Name the gas produced when zinc reacts with hydrochloric acid’ must be answered with ‘hydrogen’, not ‘a gas that pops with a lighted splint’.
‘name’ 要求写出正确的科学术语，通常涉及结构、生物、仪器或化合物。常见错误是描述而不是命名。例如：’Name the gas produced when zinc reacts with hydrochloric acid’ 必须回答 ‘hydrogen’，而不是 ‘能使带火星木条复燃的气体’。
For these low-demand questions, keep answers short and use exact scientific vocabulary. Do not repeat the question and do not add irrelevant details.
对于这些低要求题型，答案要简短并使用准确的科学词汇。不要重复题目，也不要添加无关细节。
5. Calculate | Calculate（计算）
‘Calculate’ requires you to use a formula or a numerical method to find a value. You must show your working in Edexcel IGCSE Science because method marks are often awarded even when the final answer is wrong.
‘calculate’ 需要使用公式或数值方法来求值。在 Edexcel IGCSE 科学考试中必须写出计算过程，因为即使最终答案错误，也可能获得方法分。
For example, a question may ask: ‘Calculate the acceleration of a car that changes velocity from 10 m/s to 30 m/s in 4 seconds.’ Use the formula:
a = Δv ÷ t = (30 − 10) ÷ 4 = 20 ÷ 4 = 5 m/s²
Always include units in your final answer, check your calculator display carefully, and write down each step. If a question gives values to a certain number of significant figures, match that precision when appropriate.
始终在最终答案中带上单位，仔细检查计算器显示，并写下每一步。如果题目给出的数值带有特定有效数字位数，适当保持相同的精度。
When you see ‘calculate’ in chemistry or biology, it may involve rates, concentrations, percentages, energy values or magnification. Learn all the required equations from the specification, and practise rearranging them.
在化学或生物题目中看到 ‘calculate’ 时，可能涉及速率、浓度、百分比、能量值或放大倍数。请熟记考纲中的所有公式，并练习公式变形。
6. Suggest | Suggest（提出建议/推测）
‘Suggest’ is an extension command word used when the answer is not directly taught. It asks you to apply your knowledge to a new situation. Edexcel uses ‘suggest’ to reward sensible scientific reasoning, so there is often more than one correct answer.
‘suggest’ 是一种进阶指令词，用于答案并非教材直接讲授的情况。它要求你运用已有知识解决新情境。Edexcel 用 ‘suggest’ 来奖励合理的科学推理，因此正确答案往往不止一个。
For instance: ‘Suggest why a plant grows better in green light than in red light.’ You might reason that green light reflects less energy or that pigments absorb red light more effectively. As long as your answer is biologically logical, marks are awarded.
例如：’Suggest why a plant grows better in green light than in red light.’ 你可以推理出绿色光反射较少能量，或色素吸收红光更有效。只要答案在生物学上合理，就能得分。
The best ‘suggest’ answers tend to be short and plausible. Avoid wild guesses. Connect your suggestion to known principles such as diffusion, photosynthesis, bonding or energy transfer.
最好的 ‘suggest’ 答案往往简短且合理。避免胡乱猜测。将你的建议与已知原理联系，如扩散、光合作用、化学键或能量转移。
7. Compare | Compare（比较）
‘Compare’ asks you to identify similarities and differences between two things. The most common mistake is to describe each thing separately without making direct comparisons.
‘compare’ 要求你找出两个事物之间的相同点和不同点。最常见的错误是分别描述每个事物，而没有进行直接比较。
Compare phrases should be parallel and linked by words such as ‘whereas’, ‘unlike’, ‘both’ or ‘while’. For example: ‘Compare the structure of arteries and veins. Arteries have thick muscular walls, whereas veins have thin walls. Both have a lining of endothelium.’
比较的表达应具有平行结构，并使用 ‘whereas’、’unlike’、’both’、’while’ 等连接词。例如：’Compare the structure of arteries and veins. Arteries have thick muscular walls, whereas veins have thin walls. Both have a lining of endothelium.’
If the question gives two organisms, two substances or two processes, use features from the same category: structure, function, energy, rate, etc. Aim for one similarity and at least one clear difference unless the mark scheme suggests another pattern.
如果题目给出两种生物、两种物质或两个过程，请按同一类别进行比较：结构、功能、能量、速率等。除非评分标准另有要求，否则尽量写出一个相同点和至少一个明确的差异。
8. Evaluate | Evaluate（评价）
‘Evaluate’ is one of the highest-demand command words. It asks you to make a judgement based on evidence, advantages and disadvantages, and then reach a conclusion.
‘evaluate’ 是要求最高的指令词之一。它要求你根据证据、优缺点作出判断，并得出结论。
A typical question might be: ‘Evaluate the use of nuclear power compared with wind power.’ You need to discuss benefits such as reliable output and low carbon emissions, drawbacks such as radioactive waste and high cost, then state which option is better and why.
典型问题可能是：’Evaluate the use of nuclear power compared with wind power.’ 你需要讨论优点，如输出稳定、低碳排放；缺点，如放射性废物和高成本；然后说明哪种选择更好并给出理由。
To score full marks, use a clear structure: point, evidence, balance, conclusion. Use words like ‘most importantly’, ‘however’ and ‘therefore’. Avoid sitting on the fence; the examiner expects a decision supported by your reasoning.
要拿满分，请使用清晰的结构：观点、证据、权衡、结论。使用 ‘most importantly’、’however’、’therefore’ 等词。不要模棱两可；考官期望你作出有推理支撑的决定。
9. Outline and Identify | Outline 与 Identify
‘Outline’ is similar to ‘describe’ but requires a briefer summary of the main points. You do not need every detail, just the key stages or features in a logical order.
‘outline’ 与 ‘describe’ 相似，但只需要简要概括要点。不需要写出所有细节，只需按逻辑顺序列出关键阶段或特征。
For example, ‘Outline the process of electrolysis of molten lead bromide’ could be answered in three short sentences: lead ions move to the cathode, bromide ions move to the anode, and lead and bromine are produced. This shows you know the big picture without detailed half-equations.
例如：’Outline the process of electrolysis of molten lead bromide’ 可以用三句话回答：铅离子移向阴极，溴离子移向阳极，生成铅和溴。这显示你掌握了大框架，而不必写详细的半方程式。
‘Identify’ means to pick out or name something from a graph, diagram, table or piece of text. It is often used with words like ‘identify the dependent variable’ or ‘identify the month with the highest temperature’.
‘identify’ 意思是从图表、示意图、表格或文本中选出或写出某事物。它常与以下表达搭配：’identify the dependent variable’ 或 ‘identify the month with the highest temperature’。
10. Deduce and Determine | Deduce 与 Determine
‘Deduce’ asks you to work out an answer from evidence or information given in the question. It is not simple recall; you must make a logical step forward. For example, given the ionic charge of X is 2+ and Y is 1−, you can deduce the formula of the compound is XY₂.
‘deduce’ 要求你根据题目给出的证据或信息推算出答案。这不是简单回忆，而是需要逻辑推理。例如：已知 X 的离子电荷为 2+，Y 为 1−，你可以推出该化合物化学式为 XY₂。
‘Determine’ is often used in practical contexts. It means to find a value or conclusion experimentally, or by calculation from data. For example, ‘Determine the density of a block’ requires measuring mass and volume and then dividing.
‘determine’ 常用于实验情境，意思是通过实验或数据计算求出一个值或结论。例如：’Determine the density of a block’ 需要测量质量和体积，然后进行除法运算。
When answering ‘deduce’ questions, write the evidence you used in your answer. When answering ‘determine’ questions, show the measurements and calculation clearly.
回答 ‘deduce’ 题时，请写下你所用的证据。回答 ‘determine’ 题时，请清晰展示测量过程和计算步骤。
11. How Marks Are Awarded | 分数是如何分配的
Edexcel IGCSE Science mark schemes assign each answer to a level or a specific point. Low-demand command words carry one to two marks, while high-demand words such as ‘evaluate’ carry four to six marks. The number of marks is a strong clue to the number of points needed.
Edexcel IGCSE 科学的评分标准将每个答案对应到特定分数或等级。低要求指令词一般占 1 到 2 分，而 ‘evaluate’ 等高级指令词占 4 到 6 分。分值是答案要点数量的重要线索。
The phrase ‘give one reason’ means one valid point; writing five incorrect reasons will not earn extra marks. For ‘describe’ questions, use trend words such as ‘as X increases, Y increases’ and include data from the graph if present.
‘give one reason’ 意味着只需要一个有效要点；写五个错误理由不会额外得分。’describe’ 题请使用趋势表达，如 ‘as X increases, Y increases’，如果图表中有数据要加以引用。
For ‘explain’ questions, the mark scheme often contains a ’cause and consequence’ pair. Make sure your answer includes both parts. For ‘evaluate’ questions, state a final judgement clearly, not just a list of pros and cons.
‘explain’ 题的评分标准通常包含’原因与结果’成对出现。务必确保答案涵盖两部分。’evaluate’ 题要明确写出最终判断，而不只是罗列优缺点。
12. Final Revision Tips | 最终复习建议
Start by memorising the command word definitions until they become automatic. Every time you practise a past paper, underline the command word before you write anything. This simple habit prevents you from writing too much or too little.
首先把指令词的定义记忆到能够自动反应为止。每次练习真题时，在下笔之前先划出指令词。这个简单习惯可以防止你写得过多或过少。
Create a table of command words with one example question and one model answer for each. Review this table before every mock exam and before the real IGCSE Edexcel Science examination.
制作一个指令词表格，每个指令词配上一道例题和一个示范答案。每次模拟考和正式 IGCSE Edexcel 科学考试前都复习一遍这个表格。
Finally, read the question twice. Many marks are lost because students answer the question they wanted to see, not the question that was actually asked. Let the command word guide every sentence you write.
最后，请把题目读两遍。很多失分是因为学生回答的是他们”希望看到”的问题，而不是题目真正问的问题。让指令词引导你写下的每一句话。
Published by TutorHao | Science Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
屏轩国际教育cambridge primary/secondary checkpoint, cat4, ukiset,ukcat,igcse,alevel,PAT,STEP,MAT, ibdp,ap,ssat,sat,sat2课程辅导，国外大学本科硕士研究生博士课程论文辅导