白头如新是一个成语，意思是指老年人经历了疾病或挫折后，重新恢复健康或重获幸福，就像年轻时一样。也可以形容事物恢复原貌，重新焕发生机。

读音：bái tóu rú xīn，[bái tóu]第一声、第四声；[rú xīn]第二声、第一声。

用法：作谓语、定语；常用于比喻性的描述。

例句：

1. 经过手术治疗，她的健康状况已经白头如新。

After the surgery, her health has been restored to its former state.

2. 这座城市经历了战争的洗礼后，如今已经白头如新。

After the baptism of war, this city has now been rejuvenated.

3. 他们夫妻俩结婚多年，仍然感情很好，就像白头如新的恋人一样。

After many years of marriage, their relationship is still strong, just like a couple in the honeymoon phase.

4. 这家公司经历了危机后，现在已经白头如新，业务也有了长足发展。

After going through a crisis, this company has now been rejuvenated and its business has grown significantly.

5. 我们希望通过这次活动能够让老年人感受到白头如新的快乐。

We hope that through this event, the elderly can experience the joy of being rejuvenated.

同义词及用法：重获新生、重振旗鼓、焕发生机、重获健康、恢复年轻。

编辑总结：白头如新是一个形象生动的成语，用来比喻人或事物经历了挫折后重新焕发生机。它可以用来形容个人的身体健康恢复，也可以形容事物的复兴与进步。同时，它还可以引申为对老年人的尊敬和祝福。使用这个成语能够让句子更加生动有力，给读者留下深刻印象。