Nothing like this had ever been done before, so we had to start from scratch. 从没有这方面的先例,我们不得不从头开始。Hong Kong's manufacturing industry did not start from scratch in the post-war period.战后香港的制造业并非是从零起步。There were no textbooks, so the teachers had to start from scratch.没有课本,因此教师们只得从零开始。We started from scratch with no preconceived ideas.我们是毫无成见从零做起的。