落差: drop in elevation, gap (in wages, expectations etc), disparity...
全世界: worldwide, entire world...
组成: to form, to make up, to constitute...
唱歌: to sing a song...
傻瓜: idiot, fool...
大众: the masses, the great bulk of the population, popular (of music, science etc)...
伤心: to grieve, to be broken-hearted, to feel deeply hurt...