2 sentences for 既是 (jì​shì)

1. 既是你不舒服，就早点休息吧。

   jì​shì nǐ bù shū​fu, jiù zǎo​diǎn xiū​xi ba.

   Since you are not feeling well, you should get some rest early.

   Source: Dong Chinese Dictionary

2. 他既是我的老师，又是我的朋友。

   tā jì​shì wǒ de lǎo​shī, yòu shì wǒ de péng​you.

   He is both my teacher and my friend.

   Source: Dong Chinese Dictionary