relapse

Everyone thought she was well until a sudden relapse sent her back to the hospital.在她旧病突发被再次送入医院之前，大家都以为她身体挺好的。

Patients who stop taking the medication have a higher risk of relapse. [=they are more likely to get sick again]停止用药的病人旧病复发的风险更高。

a drug addict who has had a relapse复吸毒品的瘾君子

a drug addict who has a history of relapse有复吸毒品历史的瘾君子

The program has a low rate of relapse. [=most people who use the program do not return to the bad behavior they had stopped doing]按这一方案治疗过后，复发率很低。

If you don't continue your treatment, you could relapse.如果你不继续治疗，就可能会旧病复发。

Malaria can relapse years after the original infection.疟疾可能在初次感染多年之后复发。

The country soon relapsed into chaos.国家很快再次陷入混乱。

She stayed out of trouble for a long time, but then she relapsed into her old ways.她很久没惹事了，但后来又重蹈过去的恶习。

Many former smokers relapse [=begin smoking again] in times of stress.许多曾经的吸烟者在压力大时又开始抽了起来。