Verbs take an -s for third-person singular in the present tense.

Outline for the article

• Hook: the tiny “S” that changes meaning in everyday sentences

• Quick takeaway: the correct answer is B — it marks third-person singular

• Why this matters: subject-verb harmony keeps our writing clear and natural

• How the rule works in the present tense

• Helpful nuances and common exceptions

• Real-world examples you’ll actually hear and use

• Quick checklist to keep you on track

• Warm closing: language is alive, and this is a handy anchor

The tiny but mighty S: what it does and why you’ll notice it everywhere

Have you ever listened to a friend say, “She run every morning” and thought something sounded off? That nagging sense usually comes from a subject-verb mismatch. In English, there’s a small but visible cue that helps line up who’s doing the action: add an S at the end of the verb in many present-tense statements when the subject is he, she, or it. In other words, the verb wears an “S” to match a third-person singular subject.

If you’re staring at a multiple-choice question like the one you posted, you’ll see four options. The right choice is B: Shows third-person singular subject. It’s not about future tense, past tense, or irregular verbs—the S is all about who’s performing the action in the present.

Why does that little letter make such a difference?

Think of subject-verb agreement as a partnership between two dancers. When the subject is he, she, or it, the verb shifts its steps to stay in sync. The S is the cue that says, “Hey, I’m matching a single, third-person performer.” When the subject is I, you, we, or they, the dance changes again—the base form of the verb keeps its rhythm without the extra ending.

If you write a sentence with the wrong partner, it feels clunky, almost out of breath. “She walk” sounds off to many ears, just like a beat that’s two notes too long. The rhythm matters not just for grammar nerds; it matters for clear communication in school, at work, and in everyday life.

How the S works in the present tense (the straightforward bits)

Most verbs in the present tense add -s or -es when the subject is he, she, or it. Here are the basic patterns you’ll see most days:

• Add -s to most verbs: he walks, she talks, it rains.

• Add -es to verbs that end in -o, -ch, -s, -sh, -x, or -z: he goes, she watches, it pushes.

• If a verb ends with a consonant + y, change the y to i and add -es: he carries, she studies.

• If a verb ends with a vowel + y, just add -s: he plays, she says.

That last rule is a little window into how language loves its exceptions. For the most part, you’ll see those patterns in daily speech and writing.

Irregulars and the occasional outlier

Not everything plays by the same rules. A few verbs don’t follow the standard S-ending pattern even when the subject is in the third person. The classic example is to have: I have, you have, he has, they have. Here, the word changes in a less predictable way, and that’s what makes irregular verbs… well, irregular. The be-verb is in a class of its own: I am, you are, he is, they are. So when you’re thinking about subject-verb harmony, a good instinct is to check whether you’re dealing with a regular action or one of these special cases.

You might be wondering about the future tense, or past tense, or irregular forms in other contexts. The S ending isn’t the go-to sign for those times. For future statements, English often leans on will or the be going to construction. Past tense changes are tied to the verb’s own history (regular verbs add -ed; irregulars change in many different ways). The S ending is specifically a present-tense, third-person singular tool.

Common mistakes that trip people up (and how to dodge them)

• Mistaking “he go” for “he goes.” The eye catches the missing -es and the sentence trips up readers.

• Forgetting that you, we, they don’t take the extra S. “They runs” sounds off; it should be “They run.”

• Slipping with the be-verb. If your subject is he, she, or it, you don’t always follow with a standard -s on the main verb because the be-verb changes form: “She is” not “She are.”

A few practical examples you’ll recognize

• She runs every morning. (Third-person singular subject with -s on run)

• He watches TV after dinner. (Go-to pattern with -es on watch)

• It rains a lot in spring. (Regular -s use)

• The cat chases the laser pointer. (Regular -es when needed, like chases)

• She has a spare key. (Irregular verb: has rather than haves)

• He is late today. (Be-verb + adjective; not a simple -s on a main action verb)

What about questions and negations?

Questions in the present tense often rearrange the words and still honor the S rule on the main verb. For example:

• Does she walk to school? Here, the auxiliary does carries the weight, and the main verb stays in its base form (walk), not “walks.”

Negatives follow a similar pattern:

• She does not walk to school. (The helper does carries the agreement; the main verb remains in base form)

A quick checklist you can keep in your head

• Is the subject singular and in the third person (he, she, it)? If yes, expect an -s or -es on the main verb.

• If the subject is I, you, we, they? No extra -s on the main verb.

• Does the verb end in -o, -ch, -s, -sh, -x, or -z? You’ll likely add -es.

• If the verb ends in a consonant + y, convert the y to i and add -es. If it ends in a vowel + y, just add -s.

• Watch irregulars and the be-verb separately; they don’t always follow the same pattern.

Moving from rules to real-world usage

The moment you start drafting emails, notes, or quick messages, you’ll encounter this S-enchantment more often than you think. Consider how the sentence “The report is due Friday” sounds vs “The reports are due Friday.” The difference isn’t just about grammar; it’s about the tone of your writing. The former feels tighter and more precise, the latter clearly communicates a plural subject and its action.

A few lively digressions that still circle back

• You might notice the rhythm of speech changes with emphasis. When speaking quickly, our brains rely on those tiny markers—the S, the es, the irregulars—to keep the sentence’s tempo intact.

• In writing, choosing the right voice matters. A casual blurb may lean on simpler forms, but a formal note or essay benefits from crisp subject-verb alignment.

• Language evolves, but the basics have staying power. The present-tense habit of adding -s/ -es for third-person singular is one of those anchors you can rely on when you’re reading aloud or proofreading.

A practical, not-too-hard rule set for the everyday reader

• If your subject is he, she, or it, add -s or -es to most verbs in the present tense.

• For I, you, we, they, stick with the base form of the verb (no extra ending unless required by a different construction).

• Remember common endings: -s for most verbs, -es for tough endings, and -ies when a consonant ends before a -y.

• Don’t panic over irregulars; learn a few as you go, and you’ll spot them quickly in ordinary sentences.

• Be aware of the be-verb as a special case with its own twists (is, am, are, was, were, and so on).

A closing thought: why this tiny letter matters in the bigger picture

Language is a toolkit. Small markers like the S on a verb aren’t just grammar trivia; they help readers and listeners track who’s doing what, when, and how. When you write or speak with clear subject-verb harmony, your ideas land with less friction. It’s a quiet efficiency that makes your words sound confident and thoughtful, whether you’re sharing a thought with a friend, jotting down a note, or contributing to a class discussion.

If you’re curious to keep exploring, try a simple exercise: take a few sentences about your day and test them for subject-verb agreement. Swap out the subject and see how the verb changes. You’ll feel the pattern click, almost like flipping a light switch. And if you’d like a quick mental reminder, think of the S as the signal that a single, third-person actor is on stage.

In short, the S at the end of certain verbs is a little rule with big impact. It’s the hinge on which present-tense clarity turns. And when you keep that hinge in mind—he runs, she walks, it fits—you’re building a solid foundation for clear, correct, and confident English. The right answer, once again, is B: shows third-person singular subject.