3 sentences

1. 他们中三个年龄相同——是三胞胎。

   tā​men zhōng sān​ge nián​líng xiāng​tóng— shì sān​bāo​tāi.

   Three of them are the same age—they are triplets.

   Source: CCMatrix

2. 他们不是双胞胎，而是三胞胎中的两个。

   tā​men bù​shì shuāng​bāo​tāi, ér​shì sān​bāo​tāi zhōng de liǎng​ge.

   They are not twins, but two of triplets.

   Source: CCMatrix

3. 另一位女士在66岁时成为三胞胎的母亲。

   lìng​yī wèi nǚ​shì zài66 suì shí chéng​wéi sān​bāo​tāi de mǔ​qīn.

   Another woman became the mother of triplets at 66.

   Source: CCMatrix