从头: 1.(从最初) from the beginning; [拉丁语] ab origine; ab initio 短语和例子从头儿做起 start from the very beginning2.(重新) anew; once again 短语和例子从头儿再来 start afresh; start all over again; 从头合成 de novo synthesi
从头开始: start anew; make a fresh start; take a start from the head