Verbseoul.
ㄹ stem
줄다juldato decrease, to shrink

To say to decrease, to shrink politely in the present tense, use 줄어요 (choo-ruh-yoh). Below is the full conjugation of 줄다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
줄어
choo-ruh
줄어요
choo-ruh-yoh
줍니다
choom-nee-dah
Past
줄었어
choo-ruh-ssuh
줄었어요
choo-ruh-ssuh-yoh
줄었습니다
choo-ruh-sseum-nee-dah
Future
줄 거야
chool- -guh-yah
줄 거예요
chool- -guh-yae-yoh
줄 겁니다
chool- -guhm-nee-dah

Other useful forms

Command Polite (세요)
주세요
choo-sae-yoh
Suggestion / Let's Polite (요)
줄어요
choo-ruh-yoh
Question Polite (요)
줄어요?
choo-ruh-yoh-?
Connective “and” — (고)
줄고
chool-goh
Conditional “if” — (면)
줄면
chool-myuhn
Noun form — (기)
choom