Modals - The Writing Center

Logical possibility: expresses a degree of

probability

Before: This is the fastest way to drive to

Westwood.

After: This might be the fastest way to

drive to Westwood.

Ability: shows capability

Before: Riding the bus avoids traffic.

After: Riding the bus can avoid traffic.

Necessity: expresses directness in attitude

Before: Wash your hands before preparing

food.

After: You must wash your hands before

preparing food.

Permission: shows politeness

Before: I am going to your office hours.

After: Can I go to your office hours?

The Writing Center

Modals

What this handout is about

Modal verbs (must, will, would, should, may, can, could, might, must) precede another verb.

Modals do not have subject-verb agreement or take the infinitive “to” before the next verb.

This handout shows how modals in academic writing can change a sentence’s meaning into a

prediction, suggestion, or a question. Modals can also serve a social function to show

uncertainty or politeness. They are especially common in discussion sections of research

papers.

How to use this handout

This handout is best used with a piece of writing that benefits from being subjective. Each

function alters a sentence’s perspective differently.

Strength and Frequency of Modal Verbs

In academic writing, modal verbs are most frequently used to indicate logical possibility and

least frequently used to indicate permission. The nine modal verbs are listed under each of the

functions they can perform, and are ordered from strongest to weakest for each function.

Notice that the same modal can have different strengths when it’s used for different functions

(e.g., may or can).

Most frequent Least frequent

Logical

possibility

Ability Necessity Permission

STRONGEST

weakest

possibility

must can must may

will/would could should (as advice) could

should can

may

can/could/might

Functions of Modal Verbs

This second table organizes examples of each modal by its use, also including an explanation.

Use Explanation of use Modals Examples

Logical

possibility

This use of modals hedges, or

weakens, the certainty of a

sentence. The stronger the

modal, the stronger the

possibility. Must is so strong

that it is almost forcing

something to happen. On the

opposite end, can, could, and

might are all equally weak

and show a lack of

commitment or confidence.

Strongest logical

possibility = most probable

(but still not guaranteed)

must

will

would

should

may

can

could

Those clouds must mean that it will

rain later.

As a result, the market will close

earlier than usual today.

This naïve approach would not work

well everyday.

Careful thought should be put into

important decisions.

This may ultimately lead to better

outcomes.

Careless actions can lead to

disastrous results.

Changing these settings could

might

produce more favorable results.

These factors might contribute to

the success of the project.

Ability

This use shows ability, which

is binary, rather than

possibility, which falls on a

spectrum.

Strongest ability = most

direct

can

could

The literature can be organized by

date, author, or argument.

A person who could interpret the

results assisted the researcher.

Necessity

This use gives advice or

makes a recommendation.

Strongest necessity = most

direct

must

should

A closer examination reveals that

the subject must be treated with

great care.

Our findings suggest that health

care providers should strive to be

sensitive to the needs of their

patients.

Permission

This use asks or gives

permission in the form of a

question. It almost never

appears in published academic

writing, but frequently

appears in academic

correspondence such as e-

mails, proposals, or revisions.

The strongest modal in this

use, may, is the most polite

and indirect, whereas can is

the more direct and slightly

impolite.

Strongest permission =

most polite

may

could

can

May I request a copy of the article

that you published in 1999?

Could you get back to me by

Tuesday?

Can you elaborate on the

significance or contribution of this?

The Writing Center · Campus Box #5137 · SASB North Suite 0127 · UNC-CH · Chapel Hill, NC 27599 · CSSAC Home · http://cssac.unc.edu/

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Works consulted

We consulted these works while writing the original version of this handout. This is not a

comprehensive list of resources on the handout’s topic, and we encourage you to do your own

research to find the latest publications on this topic. Please do not use this list as a model for

the format of your own reference list, as it may not match the citation style you are using. For

guidance on formatting citations, please see the UNC Libraries citation tutorial.

Celce-Murcia, Marianne and Diane Larsen-Freeman. The Grammar Book: An ESL/EFL Teacher’s

Course. 2nd edition. Boston: Heinle & Heinle, 1999.

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