it didnt become a mass commercial medium until the price of tv sets became affordable in the 1950s.

이문장을 not until 구문과 it ~that강조구문으로 바꾸려면어떻게 하니요?the increasing need for advertsers to approach online consumers set the stage on which challenging,creative young people started to generate original advertsing ideas.

이 문장 구조 분석좀 부탁드려요~~.