Speaking: Grammar in Speaking B2 - Lesson 5: Using Modals for Speculation (must be, might have) 🤔🔮💭
Objective: To understand and practice using modal verbs (must, might, may, could, can't) to express different degrees of certainty and speculation about present and past situations.
- Learn how to use modals to speculate about present situations with varying degrees of certainty.
- Learn how to use modal perfects to speculate about past situations.
- Distinguish between modals indicating strong certainty and those indicating possibility.
- Practice using these modals appropriately in spoken contexts.
When we don't know something for sure, we often speculate or make guesses. Modal verbs are essential tools for expressing these speculations and indicating how certain (or uncertain) we are. This lesson will focus on using modals like must, might, may, could, and can't to talk about possibilities and logical conclusions in both present and past contexts.
1. Speculating about the Present
When we make guesses about a current situation based on evidence or our knowledge:
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must be (Strong certainty; logical conclusion - almost sure it's true)
"Sokha isn't answering her phone. She must be busy." (I'm very sure she's busy) -
can't be / couldn't be (Strong certainty; logical conclusion - almost sure it's NOT true)
"That news can't be true! I just spoke to him." (I'm very sure it's false) -
might be / may be / could be (Possibility; uncertainty - perhaps 50% sure)
"Where's Dara? He might be at the market." (It's possible)
"This could be the best Khmer food I've ever tasted!" (Expressing a possible strong opinion)
Note: 'May be' (two words) is a modal verb + verb 'be'. 'Maybe' (one word) is an adverb meaning 'perhaps'.
2. Speculating about the Past
When we make guesses about something that happened (or didn't happen) in the past:
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must have + past participle (Strong certainty about a past event; logical conclusion)
"The ground is wet. It must have rained last night." (I'm very sure it rained) -
can't have + past participle / couldn't have + past participle (Strong certainty that something didn't happen)
"Sreyneath can't have finished all that work already! She only started an hour ago." (I'm very sure she didn't finish) -
might have / may have / could have + past participle (Possibility about a past event; uncertain)
"Why is Bora late? He might have gotten stuck in traffic." (It's a possible reason)
"She looks upset. She could have received some bad news." (Another possibility)
Note: Could have + past participle can also mean an unfulfilled past ability or opportunity (similar to 3rd conditional), e.g., "I could have gone to the beach, but I decided to stay home." This is different from speculation.
3. Expressing Degrees of Certainty
The choice of modal verb clearly shows how sure you are:
- Very Sure (90-100%): must be, must have done (for positive certainty)
- Very Sure (90-100% Not True): can't be, can't have done / couldn't be, couldn't have done (for negative certainty)
- Possible (30-70%): might be, might have done / may be, may have done / could be, could have done
Practice Activities
Activity 1: Choose the Correct Modal
Choose the most appropriate modal of speculation to complete the sentences based on the information in brackets. Click the button to hear a sample answer.
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Situation: Your friend looks very happy and is smiling a lot.
You say: "You ________ (be) very pleased about something!" (You are almost certain) -
Situation: The lights are off at your neighbor's house, and their car is gone. It's holiday season.
You say: "They ________ (go) on holiday." (It's a strong possibility/logical conclusion) -
Situation: You can't find your keys. You're not sure where they are.
You say: "I ________ (leave) them at the restaurant, or perhaps at the office." (It's possible) -
Situation: Someone claims they saw a tiger walking down Sisowath Quay in Phnom Penh yesterday.
You say: "That ________ (be) true! Tigers don't live in the city like that." (You are almost certain it's not true)
Activity 2: Making Speculations
Look at these situations. Make speculations using appropriate modal verbs.
- You see a lot of people gathered outside a shop, looking excited. What might be happening? What must be happening? What can't be happening?
- Your friend arrives an hour late for your meeting and looks very stressed. What might have happened? What could have happened?
- You hear a strange noise coming from the kitchen late at night. What could it be? What must it be (if you're brave)? What can't it be (you hope!)?
Example for situation 1:
"There might be a special promotion. Or, a celebrity could be visiting. It must be something interesting because everyone looks excited. It can't be a fire, because no one looks scared."
Activity 3: Mysterious Local Story
Think about a local story, a mystery, or an unexplained event in your area or in Cambodia. Discuss with a partner what might have happened, what could have caused it, or what people must have thought at the time. Use various modals of speculation about the past.
- Listen to the evidence: Your choice of modal often depends on how much information you have.
- Intonation matters: Your tone of voice can also convey your degree of certainty or doubt, along with the modal verb.
- Context is key: The surrounding conversation will help others understand your speculation.
- Don't confuse `may be` (modal + verb) with `maybe` (adverb):
- "He may be late." (Modal + verb: It's possible he is late.)
- "Maybe he is late." (Adverb: Perhaps he is late.)
- Practice forming modal perfects correctly: modal + have + past participle.
Summary: Modal verbs like 'must be', 'might have', 'can't be', and 'could have' are essential for expressing different degrees of certainty when speculating about present and past situations. Using them accurately allows you to share your deductions, possibilities, and interpretations in a nuanced and natural way, making your English communication richer and more sophisticated.