Research by scientists based at King's College London and Brown University, Rhode Island, suggests that immersing children in a bilingual environment before the age of four gives them the best chance of becoming fluent in both languages. They studied 108 children with normal brain development between the ages of one and six.
短语 child's play 用来形容非常容易做的一件事，小菜一碟，易如反掌。
I finished the test very quickly. It was child's play!
Stop trying to fix the car and call a professional mechanic to do the job. This is not child's play.
另一个短语 a poster child 意思是一个典范人物。
Mr Cancino went from a poor young immigrant to a powerful businessman in a decade. He is a poster boy for the 'American Dream'.