Grammar: ⚙️ Verbs in Depth: 🎭 Modals & 🌱 Non-Finite Verbs (Advanced) (B2) - Lesson 2: Modals of Deduction & Speculation - Past (must have been, might have V3, couldn't have V3)

The Grammar Lab

travel_explore

Past Deduction

ការសន្និដ្ឋានអំពីអតីតកាល

Time Detectives! We use modals + have + past participle (V3) to guess what happened in the past based on clues.

យើងប្រើទម្រង់នេះដើម្បីទាយ ឬសន្និដ្ឋានពីអ្វីដែលបានកើតឡើងក្នុងអតីតកាល ដោយផ្អែកលើភស្តុតាងដែលយើងឃើញនៅបច្ចុប្បន្ន។

done_all

done_all Must have

ប្រាកដ ៩៩% (វិជ្ជមាន)

Use must have + V3 when you feel almost certain something happened.

The street is wet. It must have rained. I am sure it rained because of the evidence. ផ្លូវសើម។ វាប្រាកដជាមានភ្លៀងធ្លាក់ហើយ។

He got 100%. He must have studied. It is the only logical explanation. គាត់បានពិន្ទុ ១០០។ គាត់ប្រាកដជាបានខំរៀនហើយ។

help_outline

help_outline Might have

អាចទៅរួច ៥០% (មិនច្បាស់)

Use might/may/could have + V3 when you think it is possible, but you are not sure.

Where is my phone? I might have left it at home. It is a possibility. តើទូរស័ព្ទខ្ញុំនៅឯណា? ខ្ញុំប្រហែលជាភ្លេចវានៅផ្ទះហើយ។

She is late. She could have missed the bus. It's a guess. នាងមកយឺត។ នាងប្រហែលជាជិះឡានក្រុងមិនទាន់ទេ។

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cancel Couldn't have

ប្រាកដ ៩៩% (អវិជ្ជមាន / មិនអាចទៅរួច)

Use couldn't/can't have + V3 when you believe it is IMPOSSIBLE that something happened.

He couldn't have stolen it. He was with me! It is physically impossible. គាត់មិនអាចលួចវាបានទេ។ គាត់នៅជាមួយខ្ញុំតើ!

You can't have finished already. It's a huge pizza! I refuse to believe it. អ្នកមិនអាចញ៉ាំអស់លឿនម្ល៉េះទេ។ វាជាភីហ្សាដ៏ធំមួយណា!

warning The "Has/Had" Trap!

Modals always take the base verb.

(កិរិយាសព្ទជំនួយ Modals ត្រូវតែបន្តដោយកិរិយាសព្ទដើមជានិច្ច គឺ "have"។ ហាមប្រើ "has" ឬ "had" ដាច់ខាត ទោះប្រធានជា He/She/It ក៏ដោយ!)

She must has gone. close

She must have gone. check

Past Deduction 🎬

Watch Teacher Sopheak explain how to act like a grammar detective. Listen to how native speakers pronounce "must have" as "must've"!

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Quick Check ⚡

ការត្រួតពិនិត្យចំណេះដឹង

done_all Certainty

The ground is wet. It ___ rained.

(ដីសើម។ វាប្រាកដជាមានភ្លៀងធ្លាក់ហើយ។)

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If I say "He couldn't have done it", what do I mean?

(បើខ្ញុំនិយាយថា "He couldn't have done it" តើខ្ញុំមានន័យថាម៉េច?)

gpp_maybe TRICKY QUESTION!

True or False:
"She might has left early."

(តើប្រយោគនេះត្រូវ ឬខុស?)

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bolt Logic

She got a 100%. She ___ studied hard.

(នាងបានពិន្ទុ ១០០។ នាងប្រាកដជាបានខំរៀនហើយ។)

travel_explore

Mission 🎯

អនុវត្តជាក់ស្តែង!

Detective travel_explore (Someone left a coffee on your desk. Who do you think it was? Write a sentence using "must have".)

help_outline

Mission 🎯

អនុវត្តជាក់ស្តែង!

Possibility help_outline (Your friend didn't call you yesterday. Why? Write a guess using "might have".)

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Mission 🎯

អនុវត្តជាក់ស្តែង!

Impossible block (Write a sentence about something you know is impossible. Use "couldn't have".)

Ask a Question 🙋‍♂️

តើអ្នកមានចម្ងល់មែនទេ? សួរគ្រូនៅទីនេះ!

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Recent Questions

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Serey 2 hours ago

Teacher, can I say "She must has forgotten" because 'she' is singular?

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SP

Sopheak Pich Teacher 1 hour ago

Hi Serey! Great question, but NO! Modals (must, might, could, should, etc.) are very bossy. They ALWAYS demand the base form of the verb after them. So it must always be "have", never "has" or "had", no matter who the subject is! 🛑

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Vireak 4 hours ago

What is the difference between "might have" and "may have"?

Reply thumb_up 10

SP

Sopheak Pich Teacher 3 hours ago

When we are talking about past deduction (guessing the past), they are exactly the same! "He might have left" and "He may have left" both mean there is a 50% chance he left. Use whichever you prefer! 💡