from scratch 白手起家;从头做起
start from scratch 从头开始;白手起家;从起跑线开始
up to scratch 达到标准
without a scratch 
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也没受伤,安然无恙 scratch the surface 只做了肤浅
研究;不深刻,不周详 scratch for oneself [美国口语]关心自身利益
scratch line n. 起跑线
on scratch 准时,正
scratch resistance 抗划伤;耐擦伤性
starting from scratch 白手起家;从零开始
scratch resistant 耐划伤性
scratch test 过敏性测验;划痕试验