The 1967 song "Can't Take My Eyes Off You" was one of Frankie Valli's biggest hits. It's been covered by dozens of artists, including rapper Lauryn Hill. Listeners of a certain age probably remember Heath Ledger's interpretation in the 1999 romantic comedy "10 Things I Hate About You." This song is also one of the first things we thought of when a listener asked us about the construction "off of."