Finding "쓰다" from "썼어요"

Forms like 썼어요 and 컸어요 can be tricky because they involve two changes at once: a past tense ending and the deletion of the stem's final vowel ㅡ .

It's important not to simply remove the ending -었어요 and treat the remaining consonant (like ㅆ ) as the stem. A consonant alone cannot be a stem.

Instead, you should learn to recognize the entire conjugated form by comparing it with the regular ㅡ-drop pattern. The correct way to analyze these forms is:

썼어요 corresponds to 쓰- + -었어요

컸어요 corresponds to 크- + -었어요

To find the dictionary form, you need to reverse the conjugation process. Start with the full form, like 썼어요 , and recognize that it came from a stem ending in ㅡ combined with the past tense ending -었어요 .

Here's the mental process:

See the form 썼어요 .

Recognize the pattern: This is the result of 쓰- + -었어요 .

You have now restored the stem: 쓰- .

Add -다 to the stem to get the dictionary form: 쓰- + -다 → 쓰다 .

Note: You don't need to think about the present tense form 써요 when analyzing the past tense. You can go directly from the past form to the stem.

The same reverse analysis applies to longer words. Instead of creating fragments like 바ㅃ or 예ㅃ , restore the complete stem that ends in ㅡ .

Past Tense Form · Analysis · Dictionary Form

바빴어요 · 바쁘- + -았어요 · 바쁘다

예뻤어요 · 예쁘- + -었어요 · 예쁘다

슬펐어요 · 슬프- + -었어요 · 슬프다

A common mistake is to simply replace the final 요 with 다 , leading to incorrect guesses like 써다 or 바빠다 .

The vowels ㅓ (in 썼어요 ) and ㅏ (in 바빴어요 ) are not part of the original stem. They appear only after the stem's ㅡ vowel is deleted and the past tense ending ( -었어요 or -았어요 ) is attached.