ESL Grammar

Deductions – Must, May, Might

The uses of “might,” “may,” and “must” for deductions are important to learn in English. These modal verbs are used to express varying degrees of certainty or probability about a situation or event. Let’s explore each of these modals and their uses, along with examples.

Might: “Might” is used to express a possibility or a deduction that is less certain than “may.” It suggests that there is a chance that something is true, but it’s not highly likely.

Example: She might be at the library. (There’s a possibility she’s at the library, but we’re not sure.)

May: “May” is used to indicate a deduction or possibility that is more certain than “might” but less certain than “must.” It shows that something is likely, but not definite.

Example: They may have already left for the party. (There’s a good chance they left, but we can’t be sure.)

Must: “Must” is used to express a strong deduction or near certainty. When using “must,” you’re almost sure that something is true, based on the evidence or information available to you.

Example: He must be the new manager. (Based on the evidence, you’re nearly certain he’s the new manager.)

Note that “must” can sometimes express a strong probability rather than an absolute certainty. In formal contexts or when you want to express absolute certainty, you can use “has to” or “have to” instead.

Example: The package has to be here by tomorrow. (You’re absolutely certain the package will arrive by tomorrow.)

Remember that these modal verbs are used for deductions or expressing probabilities, not for stating facts. When you want to express a known fact, you should use the simple present or past tense without a modal verb.

Try the handouts and lessons below for understanding and improving the use of modals for deductions.