Modal Auxiliaries

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Modal Auxiliaries

There are also quite a few helping verbs that allow you to fine-tune the exact meaning of a verb phrase. These are the modal auxiliaries, and in the chart they are organized by function:

Modal Auxiliary Function
can/could ability/possibility
may/might possibility/permission
must/ought to obligation
should obligation/condition
would condition
shall/will intention/probability

As you can see, some modals have multiple or overlapping uses. Let’s take a closer look at a few that are easily misused.


There are three ways to use shall:

1. To express a command or make a strong statement:

You shall not pass!

2. To ask a question or make a suggestion:

Shall we go to the mall?

3. To indicate the future tense:

We shall overcome.

Now here’s the rub: traditionally, rule three applies only to first person subjects. You can say I shall or we shall (both first person), but you’re not supposed to say you shall or they shall (unless you’re commanding them – see rule 1).

If you find this confusing, you can take comfort from the fact that most people use will instead to form the future tense (also in the first person). Even in formal writing will is generally acceptable (more so in North America than in Britain). But if you want to be a stickler you can go around shouting “Thou shalt use shall to indicate the future tense with first person subjects only!”

May vs. Might

Often we use may and might interchangeably, but there is a subtle difference between them: may suggests a stronger possibility than might. The latter is more hypothetical, and is especially useful to describe situations that are contrary to fact (they didn’t happen, but they might have).

Let’s first look at some examples where may and might are interchangeable:

I may order a cheese burger.

I might go for a swim later.

By contrast, the following sentences clearly require might rather than may:

If you had stopped smoking decades ago, your lungs might now be clean.

Had I not slammed on the breaks, you might now be in a hospital.

In these cases we are dealing with hypothetical situations, where might is preferred.

And that’s it for helping verbs. Use them together with transitive and intransitive verbs to form complex verb phrases.