What's the rule for then vs than?

Than compares: taller than, more than, better than. Then is about time or sequence: we ate, then we played. If you could swap in "compared to," use than. It's one of the most common errors in adult writing too, so it's worth cementing now.

What's the difference between whose and who's?

Who's is "who is" or "who has" (who's coming? who's seen it?). Whose asks about ownership (whose jacket is this?). Same apostrophe test as it's/its: expand it to two words, and if the sentence still makes sense, the apostrophe version is right.

4th grade commonly confused words

4th grade commonly confused words worksheets

By 4th grade, the confusion sets grow to include then/than, were/we're/where, whose/who's, and through/threw. The reliable tools are expanding contractions ("they're" = "they are") and asking what the sentence actually means.

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

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

The kind of sentences you'll get

Circle the letter of the word that belongs in the sentence.

starting to snow outside! It’s · Its
Answer: It’s
There are swings free right now. no · know
The trail winds a grove of ancient redwoods. threw · through

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 95 sentences, 10 to a page. All 60 of 3rd grade's sentences are here too, plus 35 more.

Some of the answers:

theiryouritsWherehearhererightThey’reWho’sWhose

Choose the word. Circle the letter of the word that belongs in the sentence. 10 questions per page.
Fix it. Write the word in parentheses that belongs in the sentence. 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

Then/than is the sleeper at this level; kids write "better then" for years if nobody flags it. The cue: than compares (taller than), then tells time (first this, then that). For whose/who's and its/it's, the apostrophe-expansion test still does all the work. Have students say the expanded version aloud every single time; the goal is a reflex.

Watch for: Spellcheck won't catch these: 'there boots' is spelled correctly, it's just the wrong word. The apostrophe versions are always two words squeezed together: they're = they are, you're = you are, it's = it is or it has. Expanding them is the test.

Common questions about 4th grade commonly confused words

What's the rule for then vs than?: Than compares: taller than, more than, better than. Then is about time or sequence: we ate, then we played. If you could swap in "compared to," use than. It's one of the most common errors in adult writing too, so it's worth cementing now.
What's the difference between whose and who's?: Who's is "who is" or "who has" (who's coming? who's seen it?). Whose asks about ownership (whose jacket is this?). Same apostrophe test as it's/its: expand it to two words, and if the sentence still makes sense, the apostrophe version is right.

Related worksheets

Ready to print one?

Need a fresh set of sentences? Download another copy.

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

Spot a mistake on this sheet? Tell us. · About these worksheets