fall down
be shown to be false or inadequate; collapse 显示不实或不足; 崩溃; 失败
The plan fell down because it proved to be too expensive. 这项计划因费用过高而告吹. fall down on sth (infml 口) fail to do sth properly or successfully 没有把某事做好
fall down on one's promises 未履行自己的诺言
He fell down on the job. 他未能把这件工作做好.