资料来源 : Webster's Revised Unabridged Dictionary (1913)

Telling \Tell"ing\, a.
   Operating with great effect; effective; as, a telling speech.
   -- {Tell"ing*ly}, adv.

资料来源 : WordNet®

tellingly
     adv : in a telling manner; "the plain manner of its style all the
           more tellingly points up the horror of the case"