Modal Verbs of Prediction & Deduction

Learn how to talk about predictions and express guesses (deductions) with modal verbs.

Modal verbs are special verbs that give other verbs more meaning. They can describe how, when, or why another action happens. Two ways that you can use modal verbs are to make predictions and deductions (guesses).


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Making Predictions

You can use modal verbs to describe how possible things are in the future.

Modal verbs that can be used for this include will, should, may, might, and could.


For example

“It will rain tomorrow” shows a different probability level than “It could rain tomorrow.”



More Examples


  • All the snow could melt by tomorrow afternoon. (there’s a low chance)

  • My sister will come to visit next week. (this will happen)

  • Our grandmother might stop by after church. (there’s a good chance this might happen)

  • My wife should give birth any day now (this is ver likely to happen).

  • Our exam could be really difficult, it depends on how nice the professor wants to be :)



Making deductions

When you want to make a guess about the possibility of something, you can use must, might, could, or may. Each one shows a certain level of certainty.





More Examples


  • You must be ready by now! = I’m guessing you are ready.

  • Dinner might be ready. = I’m guessing dinner is ready and I’m 80% sure.

  • My sister may visit this summer =I’m guessing this is 50% certain to happen.

  • I could be pregnant. = I’m guessing I’m pregnant and I’m about 30% sure of my guess.


Review how to form modal verbs in a sentence here.


Practice using modal verbs to make predictions and deductions.