What are modal auxiliaries?

The small helpers that tune a verb's strength: can, may, might, should, must, will, would. Changing the modal changes the whole sentence's force, which is exactly what the practice trains.

Why do two modals sometimes both sound right?

Because strength is a judgment. The sheet's sentences are built so the situation clearly favors one, and the answer key explains the force each sentence needs.

4th grade modal auxiliaries (can, may, must)

4th grade modal auxiliaries (can, may, must) worksheets

Fourth graders choose and write the modal a sentence's situation demands: rules take must, advice takes should, possibilities take might, permissions take may. The options appear as the cue; the reasoning is the work.

Free printable PDF worksheet, aligned to Common Core L.4.1.c.

Each print is a different sheet with its own answer key. You don't need to sign up.

The kind of sentences you'll fix

Choose the helper verb from the parentheses that fits, and write it on the line.

Advice: we (can / may / should) review the flash cards tonight before the quiz.
Fixed: Advice: we should review the flash cards tonight before the quiz.
The forecast says it (must / shall / will) clear up by noon.
I (may / might / will) feed the fish every morning; I promised.

Every print pulls a new set of sentences at this level, so a make-up test or a second sibling gets a different mix.

What's on a 4th grade sheet

4th grade sheets draw from 40 sentences, 8 to a page.

A few of the sentences:

You may borrow my kite as long as you untangle the string after.
If we hurry, we could finish the fort before dark.
Dad says I may stay up late on the night of the meteor shower.

Fix it. Choose the helper verb from the parentheses that fits, and write it on the line. 8 sentences to fix per page.

Every version prints on US Letter or A4, with its answer key on the last page.

How to teach this

Ask 'how strong is this sentence?' before choosing: is it a rule, a tip, or a maybe? Rank the modals on a strength ladder together (might, may, can, should, must) and place each sentence on the ladder before writing.

Watch for: Modals differ by strength, not grammar: can, may, might, should, and must all fit the same slot, and only the meaning picks the winner. The sentence's situation is the whole clue. May asks permission; can states ability. The distinction is fading in speech, but school writing still expects 'May I' at the door.

Common questions about 4th grade modal auxiliaries (can, may, must)

What are modal auxiliaries?: The small helpers that tune a verb's strength: can, may, might, should, must, will, would. Changing the modal changes the whole sentence's force, which is exactly what the practice trains.
Why do two modals sometimes both sound right?: Because strength is a judgment. The sheet's sentences are built so the situation clearly favors one, and the answer key explains the force each sentence needs.

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Aligned to Common Core L.4.1.c. Reviewed by the One more sheet team. Content version 241, updated October 2026.

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