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一点儿也没受伤，安然无恙

scratch the surface只做了肤浅的研究；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，正点

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