影视英语口语:了解小孩子

“了解小孩子”在英语口语里能怎么说？

蹩脚口语：know the kids very well
地道口语：down with the kids

素材来源：《暮色》
剧情简介：
贝拉的母亲再婚，于是她搬去和父亲同住。刚到新地方，贝拉一千个不适应。老爸热心介绍她同自己的老朋友比利见面，还有她儿时的玩伴雅各布，但显然她都不热络。倒是这辆送她的卡车让她喜出望外......

Jacob: I totally rebuilt the engine for you.
Bella: Come on. Oh, my gosh! This is perfect. Are you joking me? Sorry.
Billy: I told you she'd love it. I'm down with the kids.
Charlie: Oh, yeah, dude. You're the bomb.