The missing -s: why Korean students say "she go to school"

Korean verbs never change for the subject, so students carry that habit into English and drop the -s on "he goes," "she likes," and "it works." Here's the quick explanation and drills that fix it.

Park English2026-09-303 min read

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Ask a middle schooler to say "She go to school" and they will say it with total confidence. It isn't carelessness. It's a rule from their first language doing exactly what it's supposed to do, just in the wrong place.

Why this happens

In Korean, the verb form does not care who the subject is. 가다 (to go) stays 가다 whether the subject is 나 (I), 너 (you), or 그녀 (she). Korean marks tense and politeness at the end of the sentence, but it never adds a special ending just because the subject is "he" or "she." One verb form serves every subject.

English breaks that rule exactly once: in the present simple, if the subject is he, she, or it, the verb gets an -s. "I go, you go, we go, they go" but "he goes." That single exception has no equivalent in Korean, so there's nothing in a student's first language telling them it should be there. It has to be drilled in, not translated in.

Tell your class this in one line: English adds -s only for he, she, it, and only in the present. Every other subject uses the plain verb. That's the whole rule. The hard part is remembering it under pressure, mid-sentence, when they're focused on meaning, not spelling.

Word bank

WordSimple meaning
subjectthe person or thing doing the action
verbthe action word in a sentence
agreementmaking the verb match the subject
third personhe, she, it, or a name that isn't you or me

Drills, easy to hard

  1. Fill the blank. He ___ (like) pizza. She ___ (play) guitar. It ___ (rain) a lot in June.
  2. Find and fix. "My sister go to school by bus." "The teacher speak English very fast." Students circle the verb and add the missing -s.
  3. Switch the subject. Give students "I eat breakfast at 7." Ask them to rewrite it for he, she, and my dog. Three different subjects, one small change each time.
  4. Build it themselves. Ask each student to write three true sentences about a friend, a family member, or a celebrity, all in the present simple. Partner checks for the -s.
  5. Speak it. In pairs, one student describes their weekend routine using "he" or "she" (talking about their partner), no notes. This is where the mistake actually shows up, because writing gives them time to think and speaking doesn't.

So the order matters. Fill-in-the-blank builds recognition. Speaking without notes is the real test.

Sentence frames for opinions

Once students can produce the -s automatically, move them into opinions, where the grammar point hides inside real language instead of a worksheet.

  • I think ___ because ___.
  • My favorite singer ___ (verb) every day, and I think that's ___.
  • He/She usually ___ after school, and I think that's a good/bad habit.

One exception worth flagging early

"Have" doesn't follow the pattern cleanly. He/she/it uses "has," not "haves." Mention it once, put it on the board, and move on. Students will ask, so answer it before they do.

Common questions

Does this same rule apply to modal verbs like "can" or "should"?
No, and that's worth telling students directly. Modals never take -s, no matter the subject: "he can," "she should," "it might," all stay in the plain form.
Why do students who write correctly still make this mistake when speaking?
Speaking happens in real time with less room to check grammar, so a habit from their first language surfaces faster than it does on paper. That's why a speaking drill, not just a worksheet, is what actually fixes it.

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