안녕하세요 :D These sentences lack conjugations. 저는 학교에 가다. -> 저는 학교에 가요/갑니다. 지금 유리가 식당에 음식을 먹다. -> 지금 유리가 식당에서 밥/음식을 먹어요/먹습니다. 1) To conjugate verbs in Polite Informal (Its not for too formal situations) Conjugation you need to see root-final vowel. 가다 root-final vowel 가 (ㅏ) and 아 is an open vowel so you add 아요 and get 가아요 which becomes 가요. For 먹다 root-final vowel is 먹 (ㅓ) and 어 is a closed vowel so you add 어요 and you get 먹어요. 다 is an infinitive ending which is not used in conjugations that much :D [Because of the vowel conjugation, it has lots of irregulars which you will learn :)] 2) To conjugate verbs in Polite Formal Conjugation you need to see if the final consonant of the root-final syllable. We have two endings here: ㅂ니다 which is used for when final consonant doesn't exist or it's ㄹ (가다 -> 가-ㅂ니다 -> 갑니다; 알다 -> 알-ㅂ니다 -> 압니다). For other consonants you add 습니다. (먹다 -> 먹습니다) 3) When you are trying to say "at, in" but you have action (not movement) in that location you instead use 에서 :D