怎么样翻译“五岁以下的孩子”？只用介词短语，不需要定语从句。
有以下几种翻译，请帮我判断一下正误：
children under five
children under five years
children under five years old
children under five years of age
网友的表达都是可能的：
1. children under five
有关词典例句:
Nearly half of mothers with children under five have a job. 孩子不满5岁的母亲中近一半有工作。
2. children under five years
有关词典例句:
Children under two years are exempt. 两岁以下儿童免票。
3. children under five years old
有关词典例句:
Children under six years old are admitted free. 未满6岁的儿童可免费入场。
4. children under five years of age
Children under five years of age are not charged. 未满 5 岁儿童免费。
另有有关表达:
She had two children under the age of four. 她有两个不到四岁的孩子。
She’s got four children, all under the age of five. 她有四个孩子，都不到五岁。
