2 sentences for 预防 (yù​fáng — prophylactic)

1. 这种药具有预防感冒的作用。

   zhè zhǒng yào jù​yǒu yù​fáng gǎn​mào de zuò​yòng.

   This medicine has the effect of preventing colds.

   Source: Dong Chinese Dictionary

2. 采取一切必要的预防措施是非常重要的。

   cǎi​qǔ yī​qiè bì​yào de yù​fáng cuò​shī shì fēi​cháng zhòng​yào de.

   It is very important to take all necessary precautions.

   Source: Dong Chinese Dictionary