例句-1：Brenda's accident was so bad that she's had to have an operation on her hip. Except for physical therapy, she's got to stay flat on her back. If she tries walking around too much, the doctors say she won't heal properly.
除了卧病在床以外，flat on one's back还可以用来形容一个人十分无助、或是经受了惨重的失败。比如说，我的一个侄子几年前因为大学没考上十分气馁。He was flat on his back for a long time. 他为此很长时间都意志消沉。但是最后还是战胜了自己，再次参加高考，结果还考上了一所重点大学。
大家都知道，失去工作会给人带来极大的打击。不久前，因为本地一家公司的倒闭，我们邻居两口子同时失业。他们又没有多少存款可以应急，所以，they were flat on their backs. 好在他们在这里有很多亲朋好友，大家纷纷伸出援手，帮他们付了不少账单，直到他们找到新的工作，才算渡过难关。不过，下面这个例子里的篮球队员们，运气可就没有这么好了。
例句-2：With 10 seconds left on the clock, it looked like we were on our way to victory. Then our opponents scored another basket and put us flat on our backs. It was devastating to lose by 2 points to such a low-rated team!