1. used to say that something is necessary or very important
表示某事是必要或非常重要的
You must wear a seatbelt in the car.
在車上你必須繫好安全帶。
I must finish this report by tomorrow.
我必須在明天之前完成這份報告。
Must Meaning（定義、用法、例句與發音）
must
modal
快速理解
What does "Must" mean?What are 2-3 core uses of "Must"?
「must」主要表達強烈的必要性、義務或極高的可能性。
- 1
必要性與義務
EN: You must finish your homework before going out.
翻譯: 你必須在出門前完成作業。
- 2
強烈建議
EN: You must see that movie; it's fantastic.
翻譯: 你一定要看那部電影，它太棒了。
- 3
邏輯推斷（極高可能性）
EN: He's not answering. He must be asleep.
翻譯: 他沒接電話。他一定是睡著了。
- 4
規則或規定
EN: All passengers must wear seat belts.
翻譯: 所有乘客都必須繫好安全帶。
小提醒：注意：「must」在推斷用法中，是對現在情況的推測（如：He must be at home.）。若要表達對過去的推測，需用「must have + 過去分詞」（如：He must have left.）。
發音（How to Pronounce "Must" in English）
How to pronounce "Must" in English?"Must" US vs UK pronunciation
點擊下方的 US / UK 按鈕可播放發音。
Real-life Examples of "Must" from YouTube Videos
UK tells Israel not to retaliate as France set to recognise Palestinian state | BBC News
BBC News
“We have been clear, and I have been clear to the Israeli foreign minister, we have been clear to the Israeli government, that they must not do that The idea that Gaza, devastated by war, and the West Bank filled with Israeli settlements, could form a single state might seem a distant prospect, And Israel's Prime Minister, Benjamin Netanyahu, said it would never happen, saying a Palestinian state would be a terrorist state.”
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Definitions（定義）
What are the definitions of "Must"?How does "Must" change by context?
2. used to say that something is very likely or certain
表示某事極有可能或肯定會發生
You've been traveling all day. You must be tired.
你旅行了一整天，一定很累了。
It must be raining outside. I can hear the drops.
外面一定在下雨，我聽到雨滴聲了。
3. used to give a strong recommendation or advice
用於給予強烈的推薦或建議
You must try the chocolate cake here. It's amazing!
你一定要試試這裡的巧克力蛋糕，非常好吃！
If you visit Paris, you must see the Eiffel Tower.
如果你去巴黎，一定要去看看艾菲爾鐵塔。
4. something that is necessary or essential
必要或不可或缺的事物
A good dictionary is a must for language learners.
一本好字典是語言學習者的必備品。
Warm clothing is a must in the mountains.
保暖衣物在山區是必需品。
Grammar & Patterns（句型）
What are common sentence patterns for "Must"?How to make natural sentences with "Must"?
| Pattern | Meaning | Example |
|---|---|---|
| must + V (base form) | 必須（做某事） | You must finish your homework. (你必須完成你的作業。) |
| must + be + adjective/noun | 一定（是某種狀態或身分） | He must be tired after the long trip. (長途旅行後他一定很累了。) |
| must + have + past participle | 一定（已經做了某事，用於推測過去） | She must have forgotten our meeting. (她一定是忘了我們的會議。) |
| must not + V (base form) | 禁止、不准（做某事） | Visitors must not touch the exhibits. (參觀者不准觸摸展品。) |
| must not + be + adjective/noun | 一定不是（某種狀態或身分） | That must not be the correct answer. (那一定不是正確答案。) |
用法說明
How is "Must" different from similar structures?What usage mistakes are common with "Must"?
must + V 與 must be + V-ing
- must + 動詞原形 (V) 用於表達說話者認為非常可能或邏輯上必然的推論、結論或義務。
- must be + 現在分詞 (V-ing) 則用於推測某個動作「正在進行中」，強調動作發生的當下性。
- 兩者都表示強烈的推斷，但焦點不同：一個是對狀態或事實的推論，另一個是對進行中動作的推論。
對比範例： EN: You've been driving all day. You must be tired. 翻譯: 你開了一整天的車，一定累了。
EN:The lights are on and I hear music. He must be listening to his records.
翻譯:燈亮著而且我聽到音樂聲，他一定正在聽他的唱片。
must 與 have to 的語氣差異
- must 通常表達來自說話者自身（或權威方）的強烈義務、命令或主觀認為的必要性。
- have to 則更常表達來自外部規則、情況或客觀條件所要求的必要性。
- 在否定形式中，mustn't 表示「禁止」，而 don't have to 表示「不需要」。
對比範例： EN: I must finish this report by tonight. 翻譯: 我必須在今晚完成這份報告。
EN:I have to wear a uniform at work.
翻譯:我上班必須穿制服。
總結建議
一般情況下，使用 must + 動詞原形 來表達義務或強烈推斷，並注意其與 have to 在主客觀語氣上的細微差別。
易混淆對比
What is the difference between "Must" and similar words?How to choose "Must" vs alternatives?
must vs have to
must 表示說話者主觀認為必要；have to 表示客觀情況或外部規則要求。
must vs should
must 表示強制性義務或必然推論；should 表示建議或較弱的義務。
must vs ought to
must 強調必要性或強烈推論；ought to 強調道德義務或理想狀況。
口語用法
How is "Must" used in spoken English?What is the spoken vs formal difference for "Must"?
引述
在轉述他人的要求、規定或指示時，常用「must」來傳達，語氣較為客觀。 EN: My boss said we must finish the report by Friday. 翻譯: 我老闆說我們必須在週五前完成報告。
EN:The teacher told us we must hand in the assignment on time.
翻譯:老師告訴我們必須準時交作業。
語氣強調
在口語中，有時會用「must」來表達強烈的個人推測或驚嘆，而非義務。 EN: You must be exhausted after such a long trip! 翻譯: 經過這麼長的旅程，你一定累壞了！
EN:This must be the best cake I've ever tasted.
翻譯:這一定是我吃過最好吃的蛋糕。
停頓填充
在思考或組織語句時，有時會用「I must say...」或「I must admit...」作為開頭，緩和語氣或帶出個人看法。 EN: I must say, that was a brilliant performance. 翻譯: 我得說，那真是一場精彩的演出。
EN:I must admit, I was a bit nervous at first.
翻譯:我必須承認，一開始我有點緊張。
正式寫作注意：在正式或學術寫作中，表達義務時常會選用更中性的詞彙，如「have to」、「is required to」或「should」，以避免「must」可能帶有的過於直接或個人化的命令語氣。
常見短語
What common collocations use "Must"?What fixed phrases with "Must" should I remember?
must-have
must-have (noun/adj)
必備之物；不可或缺的
must-see
must-see (noun/adj)
必看的事物（如電影、景點）
must-do
must-do (noun/adj)
必做之事
must not
must not + base verb
禁止；不准
must be
must be + noun/adj
一定是（表示推測或強烈的可能性）
must mean
must mean (that) ...
必然意味著
must feel
must feel + adj
一定感覺...（表示推測他人的感受）
常見錯誤
What are common mistakes with "Must"?Which "Must" sentences look correct but are wrong?
×You must not come tomorrow if you are busy.
✓You don't have to come tomorrow if you are busy.
「must not」表示「禁止、不准」，語氣強烈。要表達「不必、不需要」應該用「don't have to」或「don't need to」。
×Yesterday I must finish my homework before going out.
✓Yesterday I had to finish my homework before going out.
「must」沒有過去式。要表達過去的「必須」，應使用「had to」。
×You must try the local food. It's quite good.
✓You should try the local food. It's quite good.
「must」表示強烈的義務或必要性，語氣很重。對於建議或推薦，使用「should」更自然、更禮貌。
×It's quiet. They must sleeping.
✓It's quiet. They must be sleeping.
「must」表示推測時，後面要接「be + V-ing」表示正在進行的動作，或「be + 形容詞/名詞」表示狀態。不可直接接動詞-ing。
×He looks tired. He must work late last night.
✓He looks tired. He must have worked late last night.
對「過去」事件的肯定推測，應使用「must have + 過去分詞」。原句的「must work」是對現在或一般習慣的推測。
×Must I help you with your homework?
✓Do you need help with your homework? / Would you like me to help you with your homework?
用「Must I...?」直接詢問對方自己是否「必須」做某事，聽起來不禮貌，像在質疑對方的要求。提供幫助時，應使用更委婉的問法。
詞形變化
What are the word forms of "Must"?What are tense/participle forms of "Must"?