1 (wiktionary) 2 (vi.wikipedia) 3 (en.wikipedia) 4 (glosbe)

Core Words Familarize yourself with the 'core words'.
Compounds Expand your vocabulary by studying more complex words built by the 'core words'.
Wordsense Learn about the wordsenses of the english term.

ETYMOLOGY

KOREAN 3.0 Eng Wordtype Etym. Gb Vie
☆☆☆ WHY Adverb 为什么 tại sao, vì sao
☆☆ WHAT MATTER Noun 什么事，怎么回事，不知为什么 việc gì, vấn đề gì, chuyện gì