2 sentences

1. 光盘和硬盘都是常见的存储介质。

   guāng​pán hé yìng​pán dōu shì cháng​jiàn de cún​chǔ jiè​zhì.

   Optical discs and hard drives are common storage media.

   Source: Dong Chinese Dictionary

2. 真空不能传声，因为声音的传播需要介质。

   zhēn​kōng bù néng chuán shēng, yīn​wèi shēng​yīn de chuán​bō xū​yào jiè​zhì.

   Sound cannot travel through a vacuum because its transmission requires a medium.

   Source: Dong Chinese Dictionary