(一). It (completely) slipped my mind. 我一下子想不起来了。

原音重现：
A:Don't you have a dentist appointment today?
你今天没有预约牙医吗？
B:Oh yeah! It completely slipped my mind.
啊，是啊！我给忘了。
英英释义：
This means "I forget it." Usually this is said as an apology that the person didn't remember something.

(二).Let me remind you. 有事情要告诉你。/记住了。/我再说一遍。

原音重现：
A:Let me remind you that you need to clean your room.
别忘了打扫你的房间。
B:OK, Mom. I'll do it this afternoon.
知道了，妈妈。我今天下午就打扫。
英英释义：
This is a way of making sure someone remembers something. It is similar to saying "Remember that..."
美剧表达：
1.Let me remind you that I am the boss here.
别忘了我才是这儿的老板。