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uploads/spring-board.jpg

spring-board 跳板;出發點,發端。

spring-cleaning

A sharp tool, or bit, was hung from a rope and jerked up and down by men jumping on a spring-board . 粗繩子上掛著銳利的工具,即鉆頭,由踏板上跳躍的人把它拉起又放下。