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Lesson 44B2

Modal Verbs of Deduction: must, can't, might have

ஊகிக்கும் வினைச்சொற்கள்

These modals let you reason aloud about something you're not certain of — deducing what must be true, what can't be true, and what might have happened, all from available evidence.

Grammar Comparison

இலக்கண ஒப்பீடு

Deduction about the present vs. deduction about the past

English

She must be tired. (present deduction) vs. She must have been tired. (past deduction, adding have + participle)

Tamil

அவளுக்கு களைப்பா இருக்கும். / அவளுக்கு களைப்பா இருந்திருக்கும். (a similar present/past split, marked with a slightly different ending)

Both languages let you reason about certainty in either the present or the past, but English marks the shift by inserting have + past participle after the modal — must be (now) becomes must have been (back then). The same layering applies to can't (impossible) and might (uncertain): can't have left, might have forgotten. Treat 'modal + have + participle' as a single grammatical unit for reasoning about the past, parallel to how Tamil's own past-tense ending shifts the same deduction backward in time.

Vocabulary

சொற்கள்

EnglishPronunciationTamil
She must be tired.shee must bee TY-erdஅவளுக்கு களைப்பா இருக்கும்.avaḷukku kaḷaippā irukkum.
She must have been tired.shee must hav been TY-erdஅவளுக்கு களைப்பா இருந்திருக்கும்.avaḷukku kaḷaippā irundhirukkum.
He can't have left already.hee kant hav left awl-RED-eeஅவன் ஏற்கனவே போயிருக்க மாட்டான்.avan ēṟkaṉavē pōyirukka māṭṭān.
They might have forgotten.thay myt hav for-GOT-enஅவங்க மறந்திருக்கலாம்.avanga maṟandhirukkalām.