Tuberculosis is respiratory tract contagion.

肺结核是呼吸道传染病。

A non-productive cough does not expel sputum from the respiratory tract.

干咳指不从呼吸道排出痰液的咳嗽。

His cough was caused by an infection of the upper respiratory tract.

他的咳嗽是由上呼吸道感染导发的。

An upper respiratory tract infection may precede all other symptoms in as many as 68.8% of patients.

l 68.8%的患者在所有症状之前有上呼吸道感染。

One feature seen in many patients is the development of lower respiratory tract early in the illness.

在许多患者身上观察到的一项特征是，疾病初期会出现下呼吸道症状。