Verb stem + -아요 / -어요 / -여요
To make a verb polite-present-tense (the everyday spoken form), drop -다 from the dictionary form to get the stem, then add one of three endings. The choice depends on the stem's last vowel: stems ending in ㅏ or ㅗ take -아요; stems with any other vowel take -어요; the verb 하다 (to do) is irregular and becomes 해요. The same form serves as a statement, a question (raise the intonation), and a polite command in many cases — Korean leans on tone to switch mood.
Find the stem first
Every Korean dictionary verb ends in -다. Chop it off and you have the stem. 가다 (to go) → 가-. 먹다 (to eat) → 먹-. 읽다 (to read) → 읽-. 하다 (to do) → 하-. The stem is what you attach endings to, and you'll do this for every tense and mood. Get used to looking for it.
Vowel harmony — picking -아요 vs -어요
Look at the last vowel of the stem. If it's ㅏ or ㅗ, attach -아요. Otherwise (ㅓ, ㅜ, ㅡ, ㅣ, ㅔ…), attach -어요. So 먹다 (stem 먹-, vowel ㅓ) → 먹어요. 읽다 (stem 읽-, vowel ㅣ) → 읽어요. The harmony is a leftover from older Korean where 'bright' and 'dark' vowels stayed in their own camps; you don't need that history, just the rule.
Vowel-stem contractions
When the stem already ends in a vowel that matches the ending, they fuse instead of doubling up. 가다 (stem 가-) + -아요 → 가아요 which contracts to 가요. 오다 (stem 오-) + -아요 → 와요 (오 + 아 collapse to 와). 보다 (stem 보-) + -아요 → 봐요. 마시다 (stem 마시-) + -어요 → 마셔요 (시 + 어 → 셔). Don't try to memorize all the contractions today — meet them as they come up and the patterns will click.
하다 → 해요 — the universal exception
하다 (to do) is the most common Korean verb and it has its own polite-present form: 해요. You'll see this everywhere because tons of nouns hook onto 하다 to make verbs: 공부 (study) + 하다 = 공부하다 (to study) → 공부해요 (I study). 일 (work) + 하다 = 일하다 → 일해요. Just memorize 해요 as a fixed form.
Questions = same form, rising tone
Korean polite-present makes questions just by rising your voice at the end. 가요 said flat = '(I) go.' 가요? said rising = 'Are you going?'. No extra word, no word-order flip. The same goes for 먹어요? ('Are you eating?'), 읽어요? ('Are you reading?'). Listen for the tone, not the spelling.
