A: Asthma is a chronic breathing disorder characterized by recurrent attacks of breathlessness and wheezing.
答：哮喘是一种慢性呼吸疾病，特征是呼吸急促和喘息反复发作。
2
Asthma is a chronic disease of the airways characterized by recurrent attacks of breathlessness and wheezing.
哮喘是一种慢性呼吸道疾病，以呼吸急促和喘息反复发作为特征。
3
Asthma is a chronic disease characterized by recurrent attacks of breathlessness and wheezing, which vary in severity and frequency from person to person.