1) cross your fingers 两指交叉以求好运

I have a big interview tomorrow! Cross your fingers for me! 我明天有一个很重要的面试啊！祝我好运吧！

2) wrapped around one's finger 能够很容易地影响别人

That little girl has her dad wrapped around her little finger. He buys her any toy she wants! 这个小姑娘能很轻易地影响她爸爸。女儿想要什么玩具他都买！

3) green thumb 某人在种花或种菜方面很有才能

My mom has a huge green thumb! She grows a huge garden every summer. 我的妈妈在园艺方面很有才！她每年夏天在花园种很多东西！

4) I can't put my finger on it. 我弄不清到底是什么。

This coffee has a very interesting flavor! But I can't put my finger on what it is. I think it's vanilla! 这杯咖啡的味道很特别，但我喝不出这到底是什么口味。我觉是香草的味道。