3 sentences

1. 您的学生证在假期期间依然有效。

   nín de xué​sheng​zhèng zài jià​qī qī​jiān yī​rán yǒu​xiào.

   Your student ID is still valid during the holidays.

   Source: Dong Chinese Dictionary

2. 凭学生证在书店买书可以享受八折优惠。

   píng xué​sheng​zhèng zài shū​diàn mǎi shū kě​yǐ xiǎng​shòu bā zhé yōu​huì.

   With a student ID, you can enjoy a 20% discount at the bookstore.

   Source: Dong Chinese Dictionary

3. 持有学生证的游客购买门票时可以免票。

   chí​yǒu xué​sheng​zhèng de yóu​kè gòu​mǎi mén​piào shí kě​yǐ miǎn piào.

   Tourists with a student ID are exempt from paying for tickets.

   Source: Dong Chinese Dictionary