Verbseoul.
하다 verb
발전하다baljeonhadato grow, to develop

To say to grow, to develop politely in the present tense, use 발전해요 (bahl-chuhn-hae-yoh). Below is the full conjugation of 발전하다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
발전해
bahl-chuhn-hae
발전해요
bahl-chuhn-hae-yoh
발전합니다
bahl-chuhn-hahm-nee-dah
Past
발전했어
bahl-chuhn-hae-ssuh
발전했어요
bahl-chuhn-hae-ssuh-yoh
발전했습니다
bahl-chuhn-hae-sseum-nee-dah
Future
발전할 거야
bahl-chuhn-hahl- -guh-yah
발전할 거예요
bahl-chuhn-hahl- -guh-yae-yoh
발전할 겁니다
bahl-chuhn-hahl- -guhm-nee-dah

Other useful forms

Command Polite (세요)
발전하세요
bahl-chuhn-hah-sae-yoh
Suggestion / Let's Polite (요)
발전해요
bahl-chuhn-hae-yoh
Question Polite (요)
발전해요?
bahl-chuhn-hae-yoh-?
Connective “and” — (고)
발전하고
bahl-chuhn-hah-goh
Conditional “if” — (면)
발전하면
bahl-chuhn-hah-myuhn
Noun form — (기)
발전함
bahl-chuhn-hahm