With debut album "19," Adele displayed an understanding of the importance of a sweeping chorus: Well-written ballads like "Chasing Pavements" and "Hometown Glory" became outstanding when their powerful hooks unfolded. "Rolling in the Deep," the first glimpse of second album "21," places a similar emphasis on its refrain but its multilayered instrumentation gives the English singer's wail a previously unheard depth. The song's mix of doo-wop backing vocals, kick drum and unadorned piano fill in the spaces between Adele's drawn-out syllables. As musically rich as "Rolling" is, however, Adele's noticeable leap in vocal confidence highlights the track. She gracefully lingers on the last line of the verses and attacks the sorrowful chorus' first words, "You could have had it all," head on. "Rolling in the Deep" showcases the all-around development of Adele as she prepares to release her second effort.