Let one's hair down.
放松，尽情享受
例句：
You should let your hair down after a busy day.
一天忙碌的工作之后，你应该让自己放松一下。
keep an eye on
留心，监督
例句：
Will you please keep an eye on my luggage?
劳驾帮我看一下行李。
Head start
开始得早，先启动
例句：
A good education gives your child a head start in life.
良好的教育会，让你的孩子在人生起跑线上领先一步。
All ears
全神贯注聆听
例句：
I am all ears. What's up?
我认真听着呢，怎么了？
Sweet tooth
喜欢吃糖或甜食
例句：
Put in more honey if you have a sweet tooth.
如果你喜欢吃甜，就多加点蜂蜜。
