"남자들이 집을 지어요."
Translation:The men build the house.
No. The verb is 짓다. "지어요" is the 해요체-Declarative conjugation as opposed to the 합쇼체-Declarative conjugation: "짓습니다".
This verb is a ㅅ-irregular verb, which means when conjugated here, we replace the ㅅ with a 으. But this final vowel gets dropped in the conjugation so we look to the vowel ㅣ for the proper conjugation.
The stem morphs like this: "짓~" to "지으~" to "지~".