📚 9630 International A-Level Physics Command Words: Applied Question Techniques | 9630国际A-Level物理指令词应用题技巧
Command words in 9630 International A-Level Physics are not just exam vocabulary – they are precise instructions that tell you exactly how to structure your answer and what the examiner is looking for. Misreading a ‘describe’ as an ‘explain’ can lose you most of the marks even if you know the physics. This guide breaks down the most common command words, explains the thinking behind each one, and gives you practical techniques to maximise your score in applied questions.
9630国际A-Level物理考试中的指令词不仅仅是考试词汇——它们是精确的指令，告诉你应该如何组织答案、考官究竟想看什么。如果把“描述”误读为“解释”，即使你懂物理原理也会丢掉大部分分数。本指南拆解最常见的指令词，解释每个指令背后的思维逻辑，并为你提供实用技巧，帮助你在应用题中拿到最高分。
1. Overview of Command Words | 指令词总览
Before tackling individual command words, it helps to see them grouped by the cognitive skill they demand. The table below summarises the key instructions that appear on paper 1, 2 and 3 of the 9630 specification. Knowing this map means you can read a sub‑question and immediately recall the expected style, length and depth of response.
在逐一攻克指令词之前，先按照它们所要求的认知技能进行分组会很有帮助。下表总结了9630考试大纲中试卷1、2和3出现的关键指令。熟悉这张地图意味着你一看到子问题，就能立即想到期望的答题风格、长度和深度。
| Command Word / 指令词 | What it asks for / 要求 | Typical marks / 典型分值 |
|---|---|---|
| State / 陈述 | Recall a fact, law or value | 1–2 |
| Define / 定义 | Give the precise meaning of a term | 1–2 |
| Calculate / 计算 | Work out a numerical answer, showing steps | 2–4 |
| Describe / 描述 | State what happens, without explaining why | 2–4 |
| Explain / 解释 | Give reasons using physical principles | 3–6 |
| Suggest / 建议 | Apply knowledge to a novel situation; the answer does not have to be unique | 2–4 |
| Evaluate / 评估 | Weigh up evidence and state a conclusion with justification | 4–6 |
| Compare / 比较 | Identify similarities and differences | 2–4 |
| Determine / 确定 | Use given data or a graph to find a quantity | 2–4 |
| Show that / 证明 | Derive a given expression or value, showing all working | 3–5 |
2. State | 陈述
The ‘state’ command expects a short, factual answer without any development. You are being asked to retrieve a piece of knowledge from your memory – a constant, a law, a unit or a simple observation. With ‘state’, never waste time on extra sentences; one correct word or phrase is enough.
“陈述”指令要求你给出简短、事实性的答案，无需任何展开。它考察的是你从记忆中提取知识的能力——一个常数、一条定律、一个单位或一个简单的观测结论。遇到“陈述”时，不要在额外句子上浪费时间；一个正确的词语或短语就足够了。
Example: ‘State the SI base unit of force.’ The answer is simply ‘newton (N)’ or ‘kg m s⁻²’, not a full sentence. Technique tip: in data‑response questions, the answer is often printed in the given text – scan the stem before writing.
示例：“陈述力的国际单位制基本单位。”答案就是“牛顿 (N)”或“kg m s⁻²”，而不是一个完整的句子。技巧提示：在图表数据题中，答案常常就印在题目所给的信息里——动笔之前先快速扫读题干。
When ‘state’ appears with a value, e.g. ‘state the half‑life from the graph’, read axes carefully and include units. A common pitfall is writing ‘5’ when the time axis is in days; always attach the unit even if the question does not explicitly repeat ‘state the value and unit’.
当“陈述”和一个数值一起出现时，例如“从图中陈述半衰期”，要仔细阅读坐标轴并带单位。常见失分点是写出“5”而时间轴是以天为单位的；即使题目没有明确重复“陈述数值和单位”，也一定要带上单位。
3. Define | 定义
‘Define’ requires the exact meaning of a physical quantity or concept, usually in the form of a word equation or a precise sentence. Impress the examiner by starting with the formula if there is one, then stating the relationship in words. This covers two common mark schemes: one mark for the equation, one for the verbal description.
“定义”要求给出一个物理量或概念的精确含义，通常以文字方程或精确的句子的形式。如果有公式，先用公式开头，再用语言陈述关系，这能给考官留下好印象。这样涵盖两种常见的评分方案：方程一分，文字描述一分。
For instance, define power: ‘Power = work done / time taken, or the rate of doing work.’ A safe technique is to write: ‘Power is defined as P = W/t, where P is power, W is work done and t is time.’ Always define the symbols you introduce. Do not use the defined term in your definition; avoid ‘density is how dense something is’.
例如，定义功率：“功率=做功/所用时间，即做功的速率。”一个稳妥的技巧是写出：“功率定义为 P = W/t，其中 P 是功率，W 是做功，t 是时间。”一定要对你引入的符号进行定义。避免在定义中使用被定义的词本身；不要写“密度就是物体有多密”这种话。
For quantities like resistivity or electric field, use the defining equation from the formula sheet and explain it: ‘resistivity ρ = RA/L, where R is resistance, A is cross‑sectional area and L is length.’ If the question says ‘define in words’, you can still write the equation as a support, but the marks are for the statement.
对于像电阻率或电场强度这样的量，使用公式表里的定义方程并加以解释：“电阻率 ρ = RA/L，其中 R 是电阻，A 是横截面积，L 是长度。”如果题目说“用文字定义”，你仍然可以把方程作为辅助写出来，但分值是针对文字陈述的。
4. Calculate | 计算
‘Calculate’ questions test your ability to select the correct equation, substitute data and handle units. Full marks are given for a correct numerical answer with the appropriate unit, but marks are also awarded for working. Always show the formula, the substitution line and the final answer to three significant figures unless stated otherwise.
“计算”题考察你选择正确方程、代入数据和处理单位的能力。如果得出带适当单位的正确数值答案，能得到全部分数，但解题步骤也会得分。务必展示公式、代入行以及最终答案（一般取三位有效数字，除非另有说明）。
Write your working downwards in a logical order: ① relevant formula, ② rearranged form if needed, ③ numbers with units, ④ calculator display, ⑤ rounded answer. For example: v = u + at → v = 0 + (9.81)(2.5) → v = 24.525 → v = 24.5 m s⁻¹ (3 s.f.). Brackets help avoid substitution errors. Cross‑check your unit cancellation; if you expected m s⁻² and got N kg⁻¹, that can still be correct because N kg⁻¹ equals m s⁻².
把你的解题步骤自上而下地写出来，遵循逻辑顺序：① 相关公式，② 必要时重排公式，③ 带单位的数字，④ 计算器显示值，⑤ 四舍五入后的答案。例如：v = u + at → v = 0 + (9.81)(2.5) → v = 24.525 → v = 24.5 m s⁻¹（三位有效数字）。使用括号有助于避免代入错误。还要复核一下单位是否约掉；如果你预期得到 m s⁻² 却得到了 N kg⁻¹，这仍然可能正确，因为 N kg⁻¹ 就等于 m s⁻²。
In multi‑step calculations, carry extra significant figures through intermediate steps and only round at the end. Use the ‘Ans’ key on your calculator wisely. If the question provides values to 3 s.f., give your final answer to 3 s.f. – matching precision shows you understand uncertainty.
在多步计算中，中间步骤要保留额外的有效数字，只在最后一步进行舍入。合理使用计算器上的“Ans”键。如果题目给出的数值是三位有效数字，你的最终答案也要取三位有效数字——精度的匹配体现了你对不确定度的理解。
5. Describe | 描述
‘Describe’ questions ask ‘what’ happens, not ‘why’. You must report observations, trends from a graph, or stages of a process. Resist the urge to write about forces or energy unless the question explicitly says ‘describe and explain’. A pure describe answer should look like a witness statement: factual, sequential and free of reasoning.
“描述”题问的是“发生了什么”，而不是“为什么”。你必须报告观测结果、图表趋势或过程的各个阶段。除非题目明确说“描述并解释”，否则要克制去写力或能量的冲动。一个纯粹的描述答案应该像一份目击证词：事实性、按顺序、不含推理。
For a graph‑based describe, use the pattern: ‘As x increases from … to …, y increases/decreases linearly/non‑linearly, reaching a maximum/minimum at …’ Quote coordinates! A typical 3‑mark describe‑graph question expects: initial value, shape of curve and end behaviour. Never just say ‘it goes up then down’.
对于基于图线的描述，使用这样的句式：“当 x 从……增加到……时，y 线性/非线性地增加/减少，在……处达到最大/最小值。” 引用坐标！一道典型的3分图表描述题期望你写出：初始值、曲线形状和末端行为。千万不要只说“它先上升后下降”。
When describing an experiment’s procedure, use numbered bullet points if the exam board allows (check with your teacher). Include the apparatus, quantities measured, variables controlled and the sequence of actions. For example: ‘1. Measure mass m using a top‑pan balance. 2. Suspend the spring vertically and attach the mass…’
在描述实验步骤时，如果考试局允许，可以使用带编号的项目符号（可以向老师确认）。内容包括仪器、测量的量、控制的变量以及操作顺序。例如：“1. 用电子天平测量质量 m。2. 垂直悬挂弹簧并挂上质量……”
6. Explain | 解释
‘Explain’ is the most frequent command word for higher‑mark questions. You must link cause and effect using physical principles, laws and mechanisms. Your answer should contain the word ‘because’ or ‘therefore’ at least once, and it should make a clear causal chain: change → physical reason → outcome.
“解释”是高分题目里最常见的指令词。你必须运用物理原理、定律和机制来联系因果。你的答案至少应包含一次“因为”或“因此”，并且要呈现出一条清晰的因果链：变化 → 物理原因 → 结果。
Structure your explain response in three layers: (1) name the relevant law or principle, e.g. Faraday’s law; (2) state how a variable changes, e.g. flux increases; (3) state the consequence with reference to the given situation, e.g. hence a larger induced emf is recorded. Always anchor your explanation in the specific scenario – ‘cutting field lines’ is better than just ‘electromagnetic induction’.
将你的解释回答构建为三层结构：(1) 说出相关定律或原理，如法拉第定律；(2) 陈述某个变量如何变化，如磁通量增加；(3) 结合给定情境说明结果，如因此记录到更大的感应电动势。始终把解释锚定在具体场景中——“切割磁感线”要好过仅说“电磁感应”。
Use precise vocabulary: ‘internal energy increases because work is done on the gas’ beats ‘it gets hotter’. For particle physics, explain by referring to conservation laws: ‘the reaction cannot occur because strangeness is not conserved’. This precision impresses examiners and targets the mark points.
使用精确的词汇：“因为对气体做功，内能增加”优于“它变热了”。在粒子物理中，借助守恒定律来解释：“该反应不可能发生，因为奇异数不守恒。”这种精确性能打动考官，并直击得分点。
7. Suggest | 建议
‘Suggest’ invites you to apply your physics knowledge to a new, sometimes unfamiliar, situation. There is often more than one acceptable answer. The examiner wants to see a sensible physical idea, even if it is speculative. You do not need to prove it – just propose a plausible mechanism and link it to core physics.
“建议”邀请你把物理知识应用到一个新的、有时并不熟悉的情境中去。通常有不止一种可接受的答案。考官想看到的是合理的物理思想，哪怕是推测性的。你无需证明它——只需提出一个看似合理的机制，并与核心物理联系起来。
When faced with a suggest question, break the stem into physical quantities. Example: ‘Suggest why a longer pendulum might give less accurate period measurements.’ Think about amplitude decay, timing uncertainty or air resistance. Write: ‘A longer pendulum has a larger moment of inertia, so air resistance could damp oscillations more noticeably over several cycles, making the exact moment of passing the fiducial mark harder to judge.’
遇到建议题时，把题干分解成物理量。示例：“建议为什么更长的摆锤可能会导致周期测量的准确性降低。”思考振幅衰减、计时不确定度或空气阻力。写出：“更长的摆锤具有更大的转动惯量，因此空气阻力可能在若干个周期内更加明显地阻尼振荡，使得通过参考标记的准确时刻更难判断。”
Always include a physics‑based reason, never just a guess. Connect to a principle: energy dissipation, wave interference, quantum uncertainty, etc. If you are stuck, ask yourself ‘what could change the result?’ and work backwards. A vague ‘experimental error’ scores nothing; specify the error type and its effect.
始终要包含一个基于物理的理由，绝不能只是猜一下。联系到某个原理：能量耗散、波的干涉、量子不确定度等等。如果卡壳了，问自己“什么会改变结果？”然后逆向推导。模糊的“实验误差”不得分；要明确误差类型及其影响。
8. Evaluate | 评估
‘Evaluate’ questions demand a balanced judgement, supported by evidence. You must present both strengths and weaknesses of a model, method or conclusion, then state your overall opinion. This is usually the last part of a long question and carries the highest marks, so a structured answer is crucial.
“评估”题要求你做出平衡的判断，并有证据支持。你必须同时陈述一个模型、方法或结论的优点与不足，然后给出你的总体意见。这通常是一道大题的最后一问，分值最高，所以结构化的回答非常关键。
Begin by identifying at least two positive aspects and two limitations. Use physics arguments: ‘The method assumes the internal resistance of the voltmeter is infinite, which is not true in reality, so the measured terminal pd is slightly lower.’ Then give your conclusion: ‘Overall, this method is suitable for a preliminary investigation but insufficient for precise determination of emf.’
开头先指出至少两个正面方面和两个局限性。运用物理论证：“该方法假设电压表内阻无穷大，这在现实中并不成立，因此测得的端电压略微偏低。”然后给出结论：“总体而言，该方法适合初步调查，但不足以精确测定电动势。”
You can use comparison keywords: more/less reliable, greater/smaller systematic error, reasonable approximation. Link your evaluation to the context – lab‑based measurements, industrial safety, or astronomical observations. A clear final verdict that matches the evidence will capture the conclusion mark.
可以使用比较性关键词：更可靠/较不可靠、更大/更小的系统误差、合理的近似。把你的评估与背景联系起来——实验室测量、工业安全或天文观测。一个清晰的、与证据相符的最终结论会帮你拿到结论分。
9. Compare | 比较
‘Compare’ requires you to identify similarities and differences between two situations, graphs, or quantities. Do not just list features separately; use connective phrases like ‘both … whereas …’ or ‘X has a larger … than Y’. The examiner wants to see direct comparative language, not two separate descriptions.
“比较”要求你指出两种情境、图线或物理量之间的相似点和不同点。不要仅仅分别罗列特征；要使用像“两者都……而……”或“X 的……比 Y 更大”这样的连接短语。考官想看到直接比较的语言，而不是两个孤立的描述。
A reliable structure for a 4‑mark compare: (1) one similarity, (2) one difference, (3) another difference (often numerical), (4) a contrasting or linking statement. Example for two springs: ‘Both obey Hooke’s law for the range shown. Spring A has a higher spring constant (gradient) than spring B. Spring B stores more elastic energy at a given extension because the area under its F–x graph is larger.’
对于一道4分的比较题，可靠的结构是：(1) 一个相似点，(2) 一个不同点，(3) 另一个不同点（通常是数值上），(4) 一个对比性或联系性的陈述。以两根弹簧为例：“在所显示范围内，两者都遵守胡克定律。弹簧 A 的弹簧常数（斜率）比弹簧 B 大。在相同伸长量下，弹簧 B 储存的弹性势能更多，因为其 F–x 图下的面积更大。”
If graphs are involved, quote data and use terms like ‘steeper gradient’, ‘higher intercept’ or ‘non‑linear above …’. In circuit comparisons, compare resistance, power output or time constants. Always keep the focus on physics quantities, not superficial appearance.
如果涉及图表，引用数据并使用“更陡的斜率”“更高的截距”或“在……以上呈非线性”等术语。在电路比较中，比较电阻、输出功率或时间常数。始终聚焦于物理量，而非表面外观。
10. Determine | 确定
‘Determine’ signals that you must work out a quantity using given information, often from a graph or a data set. It is essentially a calculation, but the data may need to be extracted first (e.g. from a tangent or intercept). The key is to show how you obtained the value, not just to state it.
“确定”意味着你必须利用所给信息（通常来自图线或数据集）算出一个量。它本质上是一种计算，但数据可能需要先提取（例如从切线或截距中）。关键在于展示你是如何得到这个值的，而不仅仅是陈述它。
When determining the gradient of a curve, draw a large tangent triangle on the graph print‑out if paper‑based, or calculate Δy/Δx clearly. Label the points you use and write the coordinates. A typical instruction: ‘Determine the acceleration at t = 2.0 s from the velocity–time graph.’ Show: a = (v₂ − v₁) / (t₂ − t₁) = (15 − 5) / (3.0 − 1.0) = 5.0 m s⁻².
当需要确定曲线的斜率时，如果是纸质考试，在打印出的图线上画一个大的切线三角形，或者清晰地计算 Δy/Δx。标记你使用的点并写出坐标。典型的指令是：“通过速度–时间图确定 t = 2.0 s 时的加速度。”展示：a = (v₂ − v₁) / (t₂ − t₁) = (15 − 5) / (3.0 − 1.0) = 5.0 m s⁻²。
For intercept‑based determinations, e.g. finding the internal resistance r from a V–I graph, write the equation ε = V + Ir, rearrange to V = −r I + ε, so r = −gradient. Show clearly how you relate the mathematical result to the physical constant. Units must emerge from your manipulation, not from guesswork.
对于基于截距的确定，例如从 V–I 图求内阻 r，写出方程 ε = V + Ir，重排为 V = −r I + ε，因此 r = −斜率。清晰地展示你如何将数学结果与物理常数联系起来。单位应该从你的推导中自然得出，而不是靠猜测。
11. Show that | 证明
‘Show that’ questions give you the answer, but you must prove it. Marks are for the working, not the result. Start from a fundamental equation, rearrange it logically, substitute the given values, and arrive exactly at the stated expression or number. Rounding errors can make you ‘fail to show’ – use exact values or fractions.
“证明”题已给出答案，但你必须证明它是正确的。分数是给过程的，而不是给结果的。从基本方程出发，逻辑地重排，代入给定数值，精准地得到所陈述的表达式或数字。舍入误差会让你“无法证明”——请使用精确值或分数。
For instance: ‘Show that the kinetic energy of the electron is about 3.2 × 10⁻¹⁶ J.’ Write: v = √(2eV/m) = √(2 × 1.60×10⁻¹⁹ × 2000 / 9.11×10⁻³¹) = 2.65×10⁷ m s⁻¹, then Eₖ = ½mv² = 0.5 × 9.11×10⁻³¹ × (2.65×10⁷)² = 3.20×10⁻¹⁶ J. The phrase ‘about’ in the question allows you to round to a reasonable precision, but clearly show the unrounded intermediate.
例如：“证明电子的动能约为 3.2 × 10⁻¹⁶ J。”写出：v = √(2eV/m) = √(2 × 1.60×10⁻¹⁹ × 2000 / 9.11×10⁻³¹) = 2.65×10⁷ m s⁻¹，然后 Eₖ = ½mv² = 0.5 × 9.11×10⁻³¹ × (2.65×10⁷)² = 3.20×10⁻¹⁶ J。题目中的“约”允许你舍入到合理的精度，但要清晰地展示未舍入的中间值。
Also use ‘show that’ for formula derivations. Link each step to a definition or a law. If you need to prove P = I²R, state: ‘P = IV from the definition of power, and V = IR from Ohm’s law. Substituting V gives P = I(IR) = I²R.’ Label the equations you combine, and your derivation will gain full marks.
还可以用“证明”来做公式推导。每一步都要与定义或定律关联起来。如果你需要证明 P = I²R，陈述：“由功率的定义得 P = IV，由欧姆定律得 V = IR。代入 V 给出 P = I(IR) = I²R。”为你所用的方程加上标注，这样你的推导就会获得全部分数。
Published by TutorHao | Physics 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