4 sentences

1. 这是他首次参加国际会议。

   zhè shì tā shǒu​cì cān​jiā guó​jì huì​yì.

   This is his first time attending an international conference.

   Source: Dong Chinese Dictionary

2. 你是何时首次触动了我的心呢？

   nǐ shì hé​shí shǒu​cì chù​dòng le wǒ de xīn ne?

   When did you first touch my heart?

   Source: OpenSubtitles

3. 麦哲伦率领船队完成了首次环球航行。

   Mài​zhé​lún shuài​lǐng chuán​duì wán​chéng le shǒu​cì huán​qiú háng​xíng.

   Magellan led his fleet to complete the first circumnavigation of the globe.

   Source: Dong Chinese Dictionary

4. 新款智能折叠手机在本次科技博览会上首次亮相。

   xīn​kuǎn zhì​néng zhé​dié shǒu​jī zài běn​cì kē​jì bó​lǎn​huì shàng shǒu​cì liàng​xiàng.

   The new smart folding phone made its debut at this technology expo.

   Source: Dong Chinese Dictionary