Mysteries of the Ancient World

Grammar Focus: Verbs of Speculation (Past)

We use these modal verbs to make logical guesses or deductions about past events, based on evidence.

• Must have + past participle: Certainty that something happened.
  Example: "They must have had advanced tools." (We are 95% sure)
• Might have / May have / Could have + past participle: Possibility that something happened.
  Example: "They might have used real soldiers as models." (It's possible, maybe 50% sure)
• Can't have / Couldn't have + past participle: Certainty that something did NOT happen.
  Example: "It can't have been a modern hoax." (We are 95% sure it was not)