rum·bling /ˈrʌmblɪŋ/
  轉筒混合; 雷鳴樣的
  Rum·bling a. & n. from Rumble, v. i.
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  rumbling
       adj : continuous full and low-pitched throbbing sound; "the
             rumbling rolling sound of thunder" [syn: grumbling]
       n : a loud low dull continuous noise; "they heard the rumbling
           of thunder" [syn: rumble, grumble, grumbling]