1. in one's second childhood 返老还童
My father bought himself a toy train, and my mother said he was in his second childhood.
我爸给自己买了一个玩具火车，我妈说他真是返老还童了。
2. sleep like a baby 睡得香
Nothing can wake me up. I usually sleep like a baby.
我睡得很沉，没什么东西能把我吵醒。
3. kid's stuff 很容易的事情
Climbing that hill is kid's stuff.
爬那座山太小儿科了。
4. like a kid with a new toy/like a kid in a candy store 很开心
Every time Bill gets a new gadget for his kitchen, he's like a kid with a new toy.
每次比尔往厨房里添个什么新物件，他都像一个得了新玩具的孩子一般高兴。
5. new kid on the block 新来者
I'm just the new kid on the block. I've only been working here for a month.
我是公司的新员工，才来了一个月。
6. latchkey kid 挂钥匙儿童（指因为父母忙于工作，放学后独自在家的孩子）
My dad came home at eight in the evening and my mom only an hour earlier so I was a latchkey kid.
小的时候我是个“挂钥匙”儿童，我爸晚上八点才回家，我妈七点回家。
7. a whizz-kid 有为青年
They've taken on some financial whizz-kid who's going to sort all their problems out.
他们请了些金融天才来帮他们解决问题。
8. a love child 私生子
He allegedly has a love child in Australia from an affair with a much younger woman.
他们说他在澳大利亚和一个很年轻的女人有一个私生子。