3 sentences

1. 他最近患上了呼吸道感染。

   tā zuì​jìn huàn​shang le hū​xī​dào gǎn​rǎn.

   He recently caught a respiratory tract infection.

   Source: Dong Chinese Dictionary

2. 流感是一种传染性很强的呼吸道疾病。

   liú​gǎn shì yī zhǒng chuán​rǎn​xìng hěn qiáng de hū​xī​dào jí​bìng.

   Influenza is a highly contagious respiratory disease.

   Source: Dong Chinese Dictionary

3. 调查显示，该地区许多居民患有呼吸道疾病。

   diào​chá xiǎn​shì, gāi dì​qū xǔ​duō jū​mín huàn​yǒu hū​xī​dào jí​bìng.

   The survey shows that many residents in the area suffer from respiratory diseases.

   Source: Dong Chinese Dictionary