Sound (sounds) great

A missing -s on a verb (The dog chase → The dog chases) is a small error that quickly marks writing as nonnative or careless. Below: crisp rules, many real sentences from work, school, and casual use, ready-to-copy rewrites, and quick checks to fix lines fast.

Focus: present simple with third-person singular subjects (he / she / it / a single noun).

Quick answer

Add -s to the main verb in present simple when the subject is third-person singular (he, she, it, or a singular noun). Use the base form for plural subjects or after auxiliaries and modals.

Correct: The dog chases the cat. (singular subject → verb + s)
Correct: Dogs chase cats. (plural subject → base verb)
Correct with auxiliary: The dog does chase the cat. (auxiliary carries the tense; main verb stays base)

Core explanation: why "The dog chase" sounds wrong

In present simple, English marks third-person singular by adding -s to most verbs: he runs, she writes, the dog chases. That -s tells the reader which single person or thing performs the action.

If the subject is plural (they, the dogs) or a modal/auxiliary controls the tense (does, will, can), the main verb remains in its base form (chase).

Third-person singular (he / she / it / a single noun) → verb + s (chases).
Plural subjects (they / we / dogs) → base verb (chase).
With auxiliaries/modals (does, do, will, can) the auxiliary changes, main verb stays base (does chase, will chase).
Exceptions: be and have have unique present forms (is, has).

Wrong: The dog chase the cat.
Right: The dog chases the cat.

Grammar basics: auxiliaries, negatives, and questions

For questions and negatives with third-person singular, use does + base verb: Does the dog chase? The dog doesn't chase. The -s appears on does, not on the main verb.

Be and have behave differently: The dog is hungry; The dog has a collar. Use their normal present forms (is, has).

Question: Does he chase the squirrel? → main verb stays chase.
Negative: She doesn't like coffee. → doesn't (does not) + like.
Contracted forms follow the same pattern: He isn't (is not); He hasn't (has not).

Wrong: He don't like the idea.
Right: He doesn't like the idea.

Real usage: work, school, and casual examples

These short sentences show common situations. Swap your subject and verb into these templates and apply the same -s rule.

Work - Wrong: The client request a meeting every week.
Work - Right: The client requests a meeting every week.
Work - Wrong: The manager write the monthly report on Friday.
Work - Right: The manager writes the monthly report on Friday.
Work - Wrong: The software team delivers the build but the release manager approve it.
Work - Right: The software team delivers the build but the release manager approves it.
School - Wrong: Every student turn in the assignment on time.
School - Right: Every student turns in the assignment on time.
School - Wrong: The class begin at 9:00 each Monday.
School - Right: The class begins at 9:00 each Monday.
School - Wrong: Each chapter include two exercises.
School - Right: Each chapter includes two exercises.
Casual - Wrong: My friend always say the funniest things.
Casual - Right: My friend always says the funniest things.
Casual - Wrong: The cat chase the laser pointer around the room.
Casual - Right: The cat chases the laser pointer around the room.
Casual - Wrong: She never miss her morning run.
Casual - Right: She never misses her morning run.

Examples: focused wrong → right pairs (copy these fixes)

Quick reference pairs showing singular subjects followed by base verbs.

Wrong: The dog chase the cat down the alley.
Right: The dog chases the cat down the alley.
Wrong: Each employee get a parking spot.
Right: Each employee gets a parking spot.
Wrong: Nobody know the answer to the question.
Right: Nobody knows the answer to the question.
Wrong: The jury decide the verdict tomorrow.
Right: The jury decides the verdict tomorrow.
Wrong: A third-party vendor supply the parts monthly.
Right: A third-party vendor supplies the parts monthly.
Wrong: The team captain encourage the players before every game.
Right: The team captain encourages the players before every game.

Try your own sentence

Test the whole sentence, not just a phrase. Context often makes the answer clear.

Rewrite help: three quick rewrites you can paste

If you're unsure which form fits, use one of these safe rewrites: correct present simple, present continuous, or a plural-subject version. Pick the one that matches the intended meaning.

Present simple (singular subject): The dog chases the cat.
Present continuous (ongoing action): The dog is chasing the cat.
Plural-subject version (if you meant more than one): Dogs chase cats.

Rewrite set: Original (wrong): The dog chase the cat. - Fixes: The dog chases the cat. / The dog is chasing the cat. / Dogs chase cats.
Rewrite set: Original (wrong): Every student study for the test. - Fixes: Every student studies for the test. / Every student is studying for the test. / Students study for the test.
Rewrite set: Original (wrong): The manager approve the budget. - Fixes: The manager approves the budget. / The manager is approving the budget. / Managers approve budgets.

Memory trick and quick checks

Two fast habits that catch missing -s:

Silently insert does after the subject. If "subject does" sounds natural, the main verb needs -s: The dog does → The dog chases.
Read only subject + verb aloud. Missing -s usually sounds wrong in the short sentence.

Quick test: Subject = "The manager" → say "The manager does" → add -s to get "The manager approves."
If a sentence has an auxiliary (does, will), check the auxiliary rather than adding -s to the main verb.

Similar mistakes to watch for

These traps often cause the same visible error. Find the true subject and match the verb number.

Indefinite pronouns (everyone, someone) are singular: Everyone wins → Everyone wins.
Collective nouns vary by meaning; in formal American English treat team/committee as singular: The committee decides.
Phrases like "along with" or "as well as" do not change the verb: The director, along with her assistants, approves the schedule.
With "or"/"nor", the verb agrees with the nearer noun: Either the students or the teacher is responsible.

Wrong: Each of the players are excited.
Right: Each of the players is excited.
Wrong: My neighbor, along with her dogs, chase the mailman.
Right: My neighbor, along with her dogs, chases the mailman.
Wrong: Either the manager or the employees handles the complaint.
Right: Either the manager or the employees handle the complaint.

Hyphenation, spacing, and punctuation: things that hide the subject

Hyphenated modifiers, long parenthetical phrases, and prepositional phrases can separate subject and verb; ignore them when checking agreement. Also check spacing around contractions so you don't accidentally break words.

Hyphenated adjective: a well-trained dog still takes verb + s: A well-trained dog chases intruders.
Ignore parenthetical phrases: The dog (and the cats) chases → subject is dog; verb remains chases.
Isolate the main subject in long phrases: The director of the new regional offices decides... → subject = director (singular).

Wrong: The dog, along with the neighborhood cats, chase the new toy.
Right: The dog, along with the neighborhood cats, chases the new toy.

FAQ

Why add -s for he/she/it?

It marks present-tense agreement for third-person singular and shows who performs the action in simple present.

When do I use chase vs chases?

Use chases when the subject is singular third-person (the dog, he, she, it). Use chase for plural subjects (they, dogs) or after auxiliaries/modals (does chase, will chase).

Is "The dog chase" ever correct?

Not in standard present-tense declarative writing. You may see it in dialect, headline compression, or nonstandard dialogue, but standard prose requires "The dog chases."

Quick method to fix agreement errors?

Find the real subject, decide if it's singular third-person, and add -s to the main verb if it is. If there's an auxiliary (does, will), change the auxiliary instead.

Do grammar checkers catch these mistakes reliably?

Most modern checkers catch common subject-verb agreement errors, especially when commas or modifiers hide the subject. Still read suggested fixes aloud to confirm the intended meaning.

Want a fast double-check?

Copy a sentence into a grammar tool to see instant subject-verb agreement fixes and rewrite options. If you're unsure between "The dog chase" and "The dog chases," a quick check will show the correct -s and offer useful alternatives you can paste directly.