Let your hair down

　　放松一下

　　例句

　　Finally, after a week of hard work and stress, she decided to let her hair down and have a fun night out with her friends.

　　终于，在一周的辛苦工作和紧张之后，她决定放松一下，和朋友们一起度过一个愉快的夜晚。

　　Cold feet

　　临阵退缩

　　例句

　　He was going to propose, but he got cold feet at the last moment.

　　他本来要求婚的，但在最后一刻他临阵退缩了。

　　Heart-to-heart

　　坦诚相谈

　　例句

　　We had a heart-to-heart talk about our relationship and cleared up misunderstandings.

　　我们就我们的关系坦诚地交谈了一次，消除了误解。

　　Keep an eye out

　　密切注意某事物或某人

　　例句

　　Could you keep an eye out for any updates on the project?

　　你能密切关注项目的任何更新吗?

　　Play it by ear

　　放松一下

　　例句

　　We don't have a strict schedule for the day, let's just play it by ear and see what we feel like doing.

　　我们今天没有严格的计划，就随机应变，看看我们想做什么。