DICT.TW Dictionary Taiwan

 drop off /ˌdrɑpˈɔf/
 脫落,讓…下車,睡著;下降,減少

 drop off
      v 1: fall or diminish; "The number of students in this course
           dropped off after the first test"
      2: change from a waking to a sleeping state; "he always falls
         asleep during lectures" [syn: fall asleep, dope off, flake
         out, drift off, nod off, doze off, drowse off]
         [ant: wake up]
      3: retreat [syn: fall back, lose, fall behind, recede]
         [ant: gain]
      4: get worse; "My grades are slipping" [syn: slip, drop away,
          fall away]