4 sentences

1. 这张车票已经过期作废了。

   zhè zhāng chē​piào yǐ​jīng guò​qī zuò​fèi le.

   This ticket has expired and is now invalid.

   Source: Dong Chinese Dictionary

2. 过期的一律作废。

   guò​qī de yī​lǜ zuò​fèi.

   All expired items are invalid.

   Source: Dong Chinese Dictionary

3. 他在考试中犯规，因此成绩被作废。

   tā zài kǎo​shì zhōng fàn​guī, yīn​cǐ chéng​jì bèi zuò​fèi.

   He cheated during the exam, so his results were invalidated.

   Source: Dong Chinese Dictionary

4. 双方商定将旧的合同作废。

   shuāng​fāng shāng​dìng jiāng jiù de hé​tong zuò​fèi.

   Both parties agreed to void the old contract.

   Source: Dong Chinese Dictionary