3 sentences

1. 别告诉你的弟弟妹妹。

   bié gào​su nǐ de dì​di mèi​mei.

   Don't tell your younger siblings.

   Source: OpenSubtitles

2. 他是我们家的大哥，一直很照顾弟弟妹妹。

   tā shì wǒ​men jiā de dà​gē, yī​zhí hěn zhào​gu dì​di mèi​mei.

   He is the eldest brother in our family and has always looked after his younger siblings.

   Source: Dong Chinese Dictionary

3. 他在家里排行最大，平时很照顾弟弟妹妹。

   tā zài jiā​lǐ pái​háng zuì dà, píng​shí hěn zhào​gu dì​di mèi​mei.

   He is the eldest in the family and usually takes good care of his younger siblings.

   Source: Dong Chinese Dictionary