clapper
/ˈklæpə(r); `klæpɚ/ n
1 piece of metal, etc fixed loosely inside a bell and making it sound by striking the side （钟铃的）击锤; 钟舌; 铃舌. =>illus at bell 见bell之插图.
2 (idm 习语) like the `clappers (Brit infml 口) very fast or hard; vigorously 很快; 很用力; 强有力地
go, run, work, etc like the clappers 一个劲儿地走、 跑、 工作等.