first-born eldest son
His eldest son Joseph carried on his father´s traditions.
他的长子约瑟夫继承了乃父的传统。
—— 柯林斯例句He was the first-born son.
他是长子。
—— 柯林斯例句The property is the birthright of the eldest child.
长子享有财产的继承权。
—— 给力词典精选Tom is my eldest son.
汤姆是我的长子。
—— 给力词典精选The King´s eldest son is the heir to the throne.
国王的长子是王位的继承人。
—— 给力词典精选