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C1 Grammar

C1Modal verbs22 min

Modal perfects: speculating about the past

Use must have, can't have, might have and should have to judge past events with the right degree of certainty.

We cannot always be sure what happened in the past. Modal verbs + have + past participle let us show how certain we are, or comment on things that should or should not have happened. At advanced level you also need to combine them with continuous and passive forms.

MeaningFormExample
Almost certain (positive)must have + past participleThe lights are off, so they must have gone home.
Almost certain (negative)can't / couldn't have + past participleThat can't have been Kofi; he's in Madrid this week.
Possiblemay / might / could have + past participleThe keys might have fallen out of my pocket.
Possibly notmay not / might not have + past participleHe might not have heard the phone ringing.
Expected but did not happenshould / ought to have + past participleThe parcel should have arrived by Friday.
Unnecessary actionneedn't have + past participleYou needn't have brought so much food.
Longer activitymodal + have been + -ingShe looked exhausted. She must have been working for hours.
Passivemodal + have been + past participleThe contract may have been signed last week.

Notice the difference between couldn't have and needn't have. The first says something was impossible (She couldn't have known), while the second says an action was done but was not required (You needn't have come). Also, can have is not normally used in positive statements: choose may, might or could have instead.

  • The bridge can't have been built before 1900; the style is far too modern.
  • I wonder why Dev did not reply. He may not have seen my message.
  • We should have booked earlier. Now every seat is taken.
  • You needn't have waited; I could have found the way myself.

Exercise 1 of 2

Choose the correct form

Choose the option that best completes each sentence.

  1. The lights are off and the door is locked, so they _____ gone home.

  2. That _____ been Kofi you saw at the station; he is in Madrid this week.

  3. I'm not sure where Ana is. She _____ stuck in traffic.

  4. You _____ a taxi; I would have collected you from the airport.

  5. The courier said the parcel _____ arrived by Friday, but it hasn't.

  6. She looked exhausted. She _____ for hours.

  7. I wonder why Dev didn't answer. He _____ the phone ringing.

  8. The bridge _____ built before 1900; the style is far too modern.

0 of 8 answered

Exercise 2 of 2

Complete the sentences

Type the correct modal perfect form of the verbs in brackets. The first word in brackets is the modal to use.

  1. Her name is on the list, so she (must / see) the email.

  2. He is very reliable; he (can't / forget) the deadline.

  3. My keys are missing. They (might / fall) out of my pocket.

  4. The hotel is now full. We (should / book) earlier.

  5. We have enough food for ten people. We (needn't / bring) so much.

  6. Their coats were soaked. They (must / wait) outside for hours.

  7. Perhaps the contract was signed last week. It (may / sign) last week.

  8. She arrived late, so she (can't / catch) the earlier bus.

0 of 8 answered

Source

Original lesson by Joy English.

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