3 sentences

1. 疫苗为何需要防腐剂？

   yì​miáo wèi​hé xū​yào fáng​fǔ​jì?

   Why do vaccines need preservatives?

   Source: United Nations

2. 谈到防腐剂，人们常常以为有害。

   tán dào fáng​fǔ​jì, rén​men cháng​cháng yǐ​wéi yǒu hài.

   When it comes to preservatives, people often think that they are harmful.

   Source: CCMatrix

3. 防腐剂可以由盐或酒精等“天然”化学物质制成。

   fáng​fǔ​jì kě​yǐ yóu yán huò jiǔ​jīng děng“ tiān​rán” huà​xué wù​zhì zhì chéng.

   Preservatives can be made of “natural” chemicals such as salt or alcohol.

   Source: CCMatrix