Modal Verbs of Probability

 In English, we often use modal verbs to express different degrees of certainty about events or situations. These modal verbs help us communicate whether something is likely to happen, possible, or impossible. Some of the most common modal verbs for probability are may, might, could, must, and can't. Each of these verbs is used to express a different level of certainty, and understanding how to use them can improve your ability to talk about future events, present situations, or past events in English.

1. May, Might, and Could: Expressing Possibility

The modal verbs may, might, and could are used when we want to express the possibility that something will happen in the future or is happening now. These verbs suggest that there is a chance, but we are not sure about the outcome.

• May: We use may when we think that something is possible but we are not certain about it. For example:

  • It may rain later today. (This means there is a chance of rain, but it is not certain.)
  • She may come to the party tonight. (We are not sure if she will come, but it's possible.)

• Might: Might is often used in the same way as may but can sound a little more uncertain or less likely. For example:

  • I might go to the gym later. (It is possible, but not guaranteed.)
  • He might be at the meeting right now. (It is a possibility, but we're not sure.)

• Could: Could is used when something is possible, but it might require certain conditions or circumstances. It can also refer to something that is happening now but in a possible, not definite, way. For example:

  • You could get a promotion if you work hard. (It is possible, but it depends on working hard.)
  • I could be wrong about this. (It is possible that I am wrong, but it is not certain.)

2. Must: Expressing Certainty

When we are very sure about something, we use must. It expresses a strong belief that something is true based on the information we have. Must is often used when we feel certain about a fact or a situation.

• She must be at work right now. (We are sure she is at work, based on what we know.)
• It must be very cold outside. (We are certain it is cold, perhaps because we can see the weather or because we feel the temperature.)

In these examples, must shows that the speaker feels confident that something is true or happening.

3. Can't: Expressing Impossibility

When we want to say that something is impossible or that we are sure something is not true, we use can't. This is the negative form of can, and it shows that we are certain something is not happening or not true.

• She can't be at the party right now; she's on vacation. (We are sure she is not at the party because she is on vacation.)
• It can't be true that he won the lottery! (We are certain that it is impossible for him to have won the lottery, likely because of certain facts or circumstances.)

In these examples, can't strongly suggests that the event or situation is not possible.

Summary

To summarize, modal verbs of probability help us express different levels of certainty about events or situations:

• May, Might, and Could express possibility (something might happen or be happening, but we are not sure).
• Must expresses certainty (we feel sure something is true or will happen).
• Can't expresses impossibility (we are sure something cannot be true or happen).

By using these modal verbs correctly, you can communicate with more precision about how certain or uncertain you are about events in the future or present.

References

Swann, J. (2019). Practical English Usage (4th ed.). Oxford University Press.

Azar, B. S., & Hagen, S. A. (2017). Understanding and Using English Grammar (5th ed.). Pearson Education.