5 sentences

1. 你应该事先通知我们。

   nǐ yīng​gāi shì​xiān tōng​zhī wǒ​men.

   You should have notified us in advance.

   Source: Dong Chinese Dictionary

2. 别说我没事先警告过你。

   bié shuō wǒ méi shì​xiān jǐng​gào guo nǐ.

   Don't say I didn't warn you.

   Source: OpenSubtitles

3. 你事先知道他们要过来吗？

   nǐ shì​xiān zhī​dào tā​men yào guò​lái ma?

   Did you know they were coming?

   Source: OpenSubtitles

4. 为什么不事先告诉我你要来？

   wèi​shén​me bù shì​xiān gào​su wǒ nǐ yào lái?

   Why didn't you tell me you were coming?

   Source: OpenSubtitles

5. 由于没人事先安排，现场乱成一团。

   yóu​yú méi rén shì​xiān ān​pái, xiàn​chǎng luàn​chéng​yī​tuán.

   Since no one had made arrangements beforehand, the scene was in total chaos.

   Source: Dong Chinese Dictionary