Modal Perfect Continuous

She must have been working all night — she looks exhausted.

Notice

  • She must have been working all night — she looks exhausted.
  • They might have been waiting for hours before we arrived.
  • He can’t have been driving that fast — the roads were icy.
  • You could have been exaggerating, but it still worried me.

Rule

Structure: modal + have been + verb-ing. This form speculates about an ongoing past action rather than a completed one, adding duration or continuity to the deduction. It’s a more nuanced, C1-level extension of the modal perfect forms you know from B2 (must have, might have, can’t have).

Practice

  1. Complete: ‘They _____ (must / travel) all day — they arrived exhausted.’
    Answer: must have been travelling
  2. Complete: ‘She _____ (can’t / sleep) — the light was off all night.’
    Answer: can’t have been sleeping
  3. Rewrite with continuity: ‘He might have studied for hours before the test.’
    Answer: He might have been studying for hours before the test.
  4. Explain the difference between ‘must have finished’ and ‘must have been finishing’.
    Answer: ‘Must have finished’ speculates about a completed action; ‘must have been finishing’ (less common, implies interruption) or better ‘must have been working on it’ speculates about an ongoing process.

Connect

Practise nuanced past speculation with modal perfect continuous forms.

Try Grammar Quiz →

CEFR: Spoken Interaction — formulate precise speculation and deduction about past events.

Azizul Hakim
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