[
{
"title": "Modal Verbs of Deduction & Possibility",
"questions": [
{
"category": "Certainty Levels",
"question": "Which modal verb shows that you are almost 100% sure something is true?",
"options": ["must", "might", "could"],
"answer": "must",
"explanation": "We use **must** for positive logical deductions when we are almost certain something is true based on strong evidence."
},
{
"category": "Negative Deductions",
"question": "When you are almost certain something is impossible or untrue, which word should you use?",
"options": ["may not", "can't", "might not"],
"answer": "can't",
"explanation": "In English, **can't** is the correct modal verb used to make a negative deduction when we are sure something is impossible."
},
{
"category": "Everyday Conversation",
"question": "In casual speech, what do native speakers often use instead of 'must' for strong guesses?",
"options": ["have to / has to", "could", "may"],
"answer": "have to / has to",
"explanation": "Phrases like 'It **has to** be true!' are very common alternatives to 'must' in everyday casual conversation."
},
{
"category": "Certainty Levels",
"question": "What level of certainty do the words 'might', 'may', and 'could' express?",
"options": ["Around 5%", "Around 50%", "Around 99%"],
"answer": "Around 50%",
"explanation": "These three modal verbs all show a 50% chance or general possibility that something is true."
},
{
"category": "Formality",
"question": "What is the main difference between using 'may' and 'might' for guessing?",
"options": ["'May' is a little bit more formal.", "'May' shows much higher certainty.", "'Might' is only used for the past tense."],
"answer": "'May' is a little bit more formal.",
"explanation": "Both words mean the same thing (50% possibility), but **may** sounds slightly more formal."
},
{
"category": "Possibilities",
"question": "Which modal verb is commonly used to describe a possibility based on choices or options?",
"options": ["must", "could", "can't"],
"answer": "could",
"explanation": "We often use **could** to suggest one possible option or choice out of many."
},
{
"category": "Fill in the Blank",
"question": "It is 40 degrees Celsius outside. It ___ be snowing outside!",
"options": ["must", "can't", "might"],
"answer": "can't",
"explanation": "Since 40°C is very hot, it is impossible for it to snow, so we use **can't**."
},
{
"category": "Fill in the Blank",
"question": "Somchai is holding a big gold trophy. He ___ be very happy!",
"options": ["can't", "might", "must"],
"answer": "must",
"explanation": "A big gold trophy is strong evidence that he is happy, making **must** the best choice."
},
{
"category": "Fill in the Blank",
"question": "The line at the food shop is very long. It ___ be delicious!",
"options": ["has to", "can't", "might"],
"answer": "has to",
"explanation": "A long line gives strong evidence, so we use the casual deduction phrase **has to**."
},
{
"category": "Fill in the Blank",
"question": "He is late for class. He ___ be stuck in traffic.",
"options": ["must", "can't", "might"],
"answer": "might",
"explanation": "Traffic is just one possible reason out of many, representing a 50% possibility."
},
{
"category": "Fill in the Blank",
"question": "Where are my keys? They ___ be in the car, but I'm not sure.",
"options": ["must", "could", "can't"],
"answer": "could",
"explanation": "The car is a possible location, but the speaker is not completely certain."
},
{
"category": "Fill in the Blank",
"question": "Take a jacket with you. It ___ get windy tonight.",
"options": ["must", "can't", "may"],
"answer": "may",
"explanation": "Windy weather is a possibility for tonight, so we use **may**."
},
{
"category": "Logical Deductions",
"question": "A classroom door is locked and the lights are off at 10:00 AM on Monday. What is a logical guess?",
"options": ["We must have class right now.", "It might be a school holiday.", "The teacher can't be absent."],
"answer": "It might be a school holiday.",
"explanation": "A dark, locked room makes class unlikely, so a holiday is a logical possibility."
},
{
"category": "Logical Deductions",
"question": "Nisa walks into the room with a very wet umbrella. What can we guess?",
"options": ["It can't be raining outside.", "It must be raining outside.", "It has to be dry outside."],
"answer": "It must be raining outside.",
"explanation": "A soaking wet umbrella provides strong, direct evidence that it is currently raining."
},
{
"category": "Logical Deductions",
"question": "Dave just finished eating a massive three-course meal. He ___ want dessert right now.",
"options": ["must", "can't", "might"],
"answer": "can't",
"explanation": "After eating a huge meal, it is highly unlikely or impossible that he wants more food."
},
{
"category": "Fill in the Blank",
"question": "I'm not sure why Sarah looks sad. She ___ have failed her exam.",
"options": ["must to", "can", "might"],
"answer": "might",
"explanation": "Because the speaker says 'I'm not sure', it indicates a 50% possibility, so we use **might**."
},
{
"category": "Certainty Levels",
"question": "If you are sure something is impossible, which modal do you use?",
"options": ["might not", "can't", "may not"],
"answer": "can't",
"explanation": "**Can't** represents total certainty that a situation is impossible."
},
{
"category": "Fill in the Blank",
"question": "You haven't slept for 24 hours! You ___ be completely exhausted.",
"options": ["could", "can't", "must"],
"answer": "must",
"explanation": "Staying awake for a whole day is strong proof that someone is definitely tired."
},
{
"category": "Logical Deductions",
"question": "The street outside is completely dry. It ___ have rained last night.",
"options": ["must", "can't", "might"],
"answer": "can't",
"explanation": "Dry streets provide clear evidence that it did not rain."
},
{
"category": "Fill in the Blank",
"question": "If you don't study for the test tomorrow, you ___ get a bad grade.",
"options": ["must", "can't", "might"],
"answer": "might",
"explanation": "Getting a bad grade is a strong possibility, but it is not a guaranteed certainty."
},
{
"category": "Fill in the Blank",
"question": "They are speaking fluent Japanese. They ___ lived in Japan before.",
"options": ["must have", "can't have", "might not have"],
"answer": "must have",
"explanation": "Speaking a language fluently provides strong evidence of past experience living there."
},
{
"category": "Logical Deductions",
"question": "The store lights are off and the gate is closed. The shop ___ closed for the evening.",
"options": ["can't be", "must be", "could"],
"answer": "must be",
"explanation": "No lights and a closed gate provide clear evidence that the shop is currently closed."
},
{
"category": "Fill in the Blank",
"question": "Look at those dark clouds in the sky! It ___ rain soon.",
"options": ["can't", "could", "must not"],
"answer": "could",
"explanation": "Dark clouds mean rain is a highly possible option, so **could** fits here."
}
]
}
]
