Verbseoul.
하다 verb
발달하다baldalhadato develop, to improve

To say to develop, to improve politely in the present tense, use 발달해요 (bahl-dahl-hae-yoh). Below is the full conjugation of 발달하다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
발달해
bahl-dahl-hae
발달해요
bahl-dahl-hae-yoh
발달합니다
bahl-dahl-hahm-nee-dah
Past
발달했어
bahl-dahl-hae-ssuh
발달했어요
bahl-dahl-hae-ssuh-yoh
발달했습니다
bahl-dahl-hae-sseum-nee-dah
Future
발달할 거야
bahl-dahl-hahl- -guh-yah
발달할 거예요
bahl-dahl-hahl- -guh-yae-yoh
발달할 겁니다
bahl-dahl-hahl- -guhm-nee-dah

Other useful forms

Command Polite (세요)
발달하세요
bahl-dahl-hah-sae-yoh
Suggestion / Let's Polite (요)
발달해요
bahl-dahl-hae-yoh
Question Polite (요)
발달해요?
bahl-dahl-hae-yoh-?
Connective “and” — (고)
발달하고
bahl-dahl-hah-goh
Conditional “if” — (면)
발달하면
bahl-dahl-hah-myuhn
Noun form — (기)
발달함
bahl-dahl-hahm