Modal Verbs of Probability

Modal Verbs of Probability

Modal verbs of probability are a set of auxiliary verbs in English that we use to express different degrees of certainty, possibility, and even impossibility about a situation. They are essential in conveying not just what might happen, but how likely we think something is.

Here are some key modal verbs of probability and how to use them:

Must

Use must when you have strong evidence or logical reasons to believe something is true.

• She must be exhausted after running that marathon.
• Judging by the dark clouds, it must be about to rain.
• You must be tired after that long journey.

In deductions about the present or past, must have + past participle is used.

• He must have forgotten his keys.
• It must have rained last night; the ground is really wet.
• There’s no trace of the coffee on the counter; he must have already drunk it. 

Might / May / Could

We use might, may and could when we are less certain about a situation, expressing possibility rather than certainty.

• It might rain later.     
• He may be at home.
• They could be on their way.

Although might, may and could are often interchangeable in expressing possibility, might sometimes implies a slightly lower probability.

With past events, you can use might have/may have/could have + past participle

• They might have left.
• She may have been the one who organised the event.
• The restaurant could have closed earlier than usual, which is why we didn’t get a table.

Can’t

Use can’t when you want to indicate that something is highly unlikely or impossible.

• She can’t be the one to blame; all the evidence points in someone else’s direction.
• That can’t be the right key; it doesn’t even fit the lock.
• It can’t be raining right now – the sky is completely clear.

To express improbability in the past, use can’t have + past participle.

• He can’t have missed the train; his alarm went off on time.
• They can’t have finished the project already, considering it was assigned only yesterday.
• She can’t have forgotten our meeting since she confirmed it this morning. 

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