YOU SAID:

Been designing a caste system for the past 5 years in his office

INTO JAPANESE

彼のオフィスで過去5年間カーストシステムを設計してきました

BACK INTO ENGLISH

Has designed caste systems in his office for the past 5 years

INTO JAPANESE

過去5年間、彼のオフィスでカーストシステムを設計してきました

BACK INTO ENGLISH

Has designed caste systems in his office for the past 5 years