gray softening

例句：

1. 1. The patient's condition worsened after the surgery, and he started to show signs of gray softening.
   手术后，患者的病情恶化，开始出现灰质软化的迹象。
2. 2. Gray softening is a common complication in patients with Alzheimer's disease.
   灰质软化是阿尔茨海默病患者的常见并发症。
3. 3. In the study, researchers found that gray softening could be prevented by regular exercise.
   研究中，研究人员发现，通过定期锻炼可以预防灰质软化。