son and heir

例句：

1. 1.The son is studying in a foreign country.
   儿子正在国外学习。
2. 2. The heir to the throne will inherit the kingdom.
   王位的继承人将继承王国。
3. 3. The son was born with a rare genetic disorder.
   儿子出生时患有一种罕见的遗传病。