3 sentences

1. 你父亲是我们的一员。

   nǐ fù​qīn shì wǒ​men de yī​yuán.

   Your father was one of us.

   Source: OpenSubtitles

2. 他在户口簿上注了名字，正式成为了这里的一员。

   tā zài hù​kǒu​bù shàng zhù le míng​zi, zhèng​shì chéng​wéi le zhè​lǐ de yī​yuán.

   He registered his name in the household register and officially became a member here.

   Source: Dong Chinese Dictionary

3. 他在五十岁时被封为勋爵，成为了上议院的一员。

   tā zài wǔ​shí suì shí bèi fēng​wéi xūn​jué, chéng​wéi le Shàng​yì​yuàn de yī​yuán.

   He was created a peer at fifty and became a member of the House of Lords.

   Source: Dong Chinese Dictionary