eldest child大儿子
eldest son长子;年龄最大的儿子;长男;年龄最长的儿子
You Eldest各位老大
elder eldest只能作定语;表示长辈关系;做定语
eldest brother大哥
eldest sister大姐;最年长的姐;长姊
eldest farfarther特殊情况
eldest daughter长女
eldest grandson长子的长子;最年长的孙子;长孙
ADJ（形容词） The eldest person in a group is the one who was born before all the others. 年龄最大的
The eldest child was a daughter called Fatiha.
最大的孩子是个女儿叫法蒂哈。