Mr white once coached her for the olympics

问题描述:

Mr white once coached her for the olympics

once (曾经),是副词,修饰动词coached(训练,指导);
指导的对象是her,目的用for引出,"for olympics", 即"为了奥林匹克运动会而训练她";
完整的句子可翻译为:Mr White 曾经训练她以参加奥运会.