1. On pins and needles 坐立不安，如坐针毡
It seems that you're on pins and needles today. Anything troubling you?
你今天似乎坐立不安，有什么事吗？
释义：
pins：大头针；needles：指针
be on pins and needles：直译是如坐在大头针和针上，比喻坐卧不安。
2. On the dot 准时，准点
He arrived at 9 on the dot. I thought he'd be late.
他9点准时到了。我本以为他会迟到。
释义：
dot：点，准点，准确时间
