serious disease

例句：

1. 1. The patient was diagnosed with a serious disease.
   病人被诊断出患有一种严重的疾病。
2. 2. The doctor advised the patient to seek medical help for his serious disease.
   医生建议病人寻求医疗帮助治疗他的严重疾病。
3. 3. The patient's condition worsened after receiving treatment for his serious disease.
   经过治疗后，病人的病情恶化了。