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1.infancy 婴幼儿时期
学龄儿童应该接受教育。
3.adolescence 青春期Adolescence is a key period in one's life.
青春期在人的一生中至关重要。
4.thirties 而立之年He is in his thirties.
他处在而立之年。
5. middle age 中年
He showed his talents in his infancy.
他在婴儿时期就展现出了天赋。
2.school children 学龄儿童（6-12岁）
School children should receive education.
3.adolescence 青春期
4.thirties 而立之年
5. middle age 中年
Mother is entering into her middle age.
妈妈正在步入中年。
