the young and the old

• 青年与老年人

the young and the old的用法和样例：

例句

1. Babies and very old people totter as they walk.
   小孩与老年人走路蹒跚。
2. This crossover in the proportions of young and old reflects both improved survival and reduced fertility.
   年轻人与老年人人口比率的逆转，是寿命增加与生育率下降的后果。