[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"grammar-page-en-must-and-cant-dedcutions":3,"grammar-exercises-by-page-019b84b5-2659-784a-9965-86ec3a2f4271":71},{"id":4,"title":5,"slug":6,"content":7,"language":8,"level":9,"displayOrder":10,"grammarTopics":11,"createdAt":65,"updatedAt":66,"generatorCategories":67,"readyImages":69,"ogImageUrl":70},"019b84b5-2659-784a-9965-86ec3a2f4271","Must and Can't (Deductions)","must-and-cant-dedcutions","Sometimes we make guesses about situations based on evidence or facts. This is called a **deduction**. A **deduction** is a “smart guess” based on clues (evidence). Modals like **must** and **can’t** help us express how certain we are about these guesses.\n\n## 1\\. What a deduction is\n\nA **deduction** is a logical conclusion you make when you look at the evidence and decide what is likely or unlikely.\n\n### Examples\n\n* “The lights are on. Someone must be home.” → Evidence: lights are on → deduction: someone is probably home\n* “The kitchen is cold, and the stove is off. They can’t be cooking now.” → Evidence: kitchen cold + stove off → deduction: it’s impossible that they are cooking now\n\n**Note:** Deduction is about using clues to make a logical guess — not guessing randomly.\n\n## 2\\. Using must for strong deductions\n\nUse **must** when the evidence makes you feel **very sure** something is true (a strong logical conclusion). If you are not sure, use **might\u002Fmay\u002Fcould** (not covered here).\n\n**Note:** Here, **must** is not an obligation; it means ‘I’m sure this is true.’\n\nForm:\n\n* Now (state\u002Fgeneral): **must + verb (infinitive without ‘to’)** (must be \u002F must know)\n* Now (in progress): **must be + -ing** (must be sleeping \u002F must be eating)\n* Past: **must have + past participle** (must have forgotten \u002F must have slept)\n\nExamples:\n\n* “She must be tired. She worked all night.”\n* “It’s so quiet in the house. Everybody must be sleeping.”\n* “He must have been in the sun. He is sunburned.”\n\n## 3\\. Using can’t for strong negative deductions\n\nUse **can’t** when the evidence makes you **sure it’s impossible \u002F not true**.\n\nForm:\n\n* Now (state\u002Fgeneral): **can’t + base verb** (can’t be \u002F can’t live)\n* Now (in progress): **can’t be + -ing** (can’t be snowing \u002F can’t be working)\n* Past: **can’t have + past participle** (can’t have finished \u002F can’t have gone)\n\nHere, **can’t** means “it’s impossible (I’m sure)”.\n\nExamples:\n\n* “He can’t be at home. His car isn’t here.”\n* “He can’t be working right now. He’s in the café with his children.”\n* “She can’t have finished the project already. She started it yesterday.”\n\n## 4\\. Key takeaway\n\n* **Must** → strong logical certainty, very likely to be true\n* **Can’t** → strong logical impossibility, very unlikely or impossible\n* Deductions are based on **evidence**, not random guessing","en","B1",66,[12],{"id":13,"name":14,"level":9,"language":8,"isCompleted":15,"completionPercentage":16,"totalExercises":17,"completedExercises":16,"vocabularyLists":18},"019aef28-476f-7f36-98f5-cc0a235a6077","Must and Can't for Deduction",false,0,2,[19],{"id":20,"title":21,"grammarTopic":22,"displayOrder":23,"vocabularyListWords":24,"isPublished":37},"019e4ec9-0600-73b1-9b37-d9bff761f272","Deductions (Must and can't)","\u002Fapi\u002Fgrammar_topics\u002F019aef28-476f-7f36-98f5-cc0a235a6077",37.7,[25,43],{"id":26,"vocabularyWord":27,"displayOrder":38},"019e4ec9-85ad-7132-9a29-e92480d3eb6c",{"id":28,"word":29,"frequency":30,"level":9,"language":8,"partsOfSpeech":31,"audio":15},"019bdbe2-4bad-7943-9a20-be293a65cf28","must",9,[32,39],{"id":33,"partOfSpeech":34,"definition":35,"exampleSentences":36,"isPrimary":37,"meaningOrder":38},"019bdbe2-624a-7d2e-99b7-31d8cf0c5d74","VERB","Used to express necessity or obligation.","You must finish your homework before going out.\nI must remember to call my friend.",true,1,{"id":40,"partOfSpeech":34,"definition":41,"exampleSentences":42,"isPrimary":15,"meaningOrder":17},"019bdbe2-624a-7df2-99b7-31d8cf1e59e5","Used to indicate a strong recommendation or conclusion.","You must try the chocolate cake; it's delicious!\nShe must be very talented to win that award.",{"id":44,"vocabularyWord":45,"displayOrder":17},"019e4eca-1797-735d-88ba-e2ecdbd57d03",{"id":46,"word":47,"frequency":30,"level":48,"language":8,"audioFilePath":49,"partsOfSpeech":50,"audio":37,"audioUrl":64},"019b850c-a402-7aca-be1e-5bc68ed2432f","can","A1","tts_3e0f83748dd26434_en-US.mp3",[51,56,60],{"id":52,"partOfSpeech":53,"definition":54,"exampleSentences":55,"isPrimary":37,"meaningOrder":38},"019b8518-d646-7a8f-a705-088eaf0f45d3","NOUN","A container, typically cylindrical, used for storing liquids or food.","I opened a can of soup for dinner.\nThe can was made of aluminum.",{"id":57,"partOfSpeech":34,"definition":58,"exampleSentences":59,"isPrimary":37,"meaningOrder":38},"019b8518-d647-7eef-9862-9680a8f1b269","To be able to; have the ability to.","I can swim very well.\nCan you help me with this problem?",{"id":61,"partOfSpeech":34,"definition":62,"exampleSentences":63,"isPrimary":15,"meaningOrder":17},"019b8518-d647-7f3b-9862-9680a9eff156","To preserve food in a sealed container.","We can vegetables to enjoy them all year.\nShe learned how to can fruit during the summer.","\u002Fuploads\u002Faudio\u002Ftts_3e0f83748dd26434_en-US.mp3","2026-01-03T16:33:43+00:00","2026-07-14T17:37:43+00:00",[68],"grammar_exercise_questions_modality",[],"\u002Fuploads\u002Fimages\u002Fog_019b84b5-2659-784a-9965-86ec3a2f4271.jpg?v=1784050663",[72,79],{"@id":73,"@type":74,"id":75,"grammarPage":76,"title":77,"instructions":78,"displayOrder":16,"isCompleted":15},"\u002Fapi\u002Fgrammar_exercises\u002F019d3eb5-b564-7492-beb8-0dc78b9e7548","GrammarExercise","019d3eb5-b564-7492-beb8-0dc78b9e7548","\u002Fapi\u002Fgrammar_pages\u002F019b84b5-2659-784a-9965-86ec3a2f4271","Must and Can't - Mystery Dinner Party","Read each sentence carefully and decide what is possible or impossible.\nClick on each blank and choose the correct answer (must or can’t) from the dropdown menu.\nSome sentences have more than one blank, so make sure you complete all of them.",{"@id":80,"@type":74,"id":81,"grammarPage":76,"title":82,"instructions":78,"displayOrder":38,"isCompleted":15},"\u002Fapi\u002Fgrammar_exercises\u002F019d3eb5-b564-7e9a-beb8-0dc78c01ae2e","019d3eb5-b564-7e9a-beb8-0dc78c01ae2e","Must and Can't - Travel Clues"]