影视英语口语:捉摸不透

“捉摸不透”在英语口语里能怎么说？

初级口语：understandable
地道口语：can't put finger on

素材来源：《好好先生》
剧情简介：
曾经因为离婚而消极度日的银行职员卡尔经过某励志讲座的洗脑，决定对生活的所有选择都说Yes！他的人生观和价值观发生了天翻地覆的改变，并结识了生活丰富的美女 Allison......

Allison: I can't put my finger on you. You're kind of uNPRedictable. Kind of mysterious.
Carl: You know, listen. I like to keep it fresh. I like to live it up. I like to mix it up. If that doesn't jive with you, we should end this.
Allison: I love that.
Carl: I don't know how people go through life with the same boring routine.
Allison: Just shoot me.
Carl: I know. Right in the face.