On the dot
正点，准时的
exactly at the stated or expected time
Examples
The train arrived on the dot of three o'clock.
那辆火车三点钟准时到达。
It was also finite, easy to do well, and ended on the dot of 6pm.
工作令人开心，工作量也有限，容易干好，而且能够下午6点准时下班。
He arrives on the dot. I was sure he’d be late.
他准时到了。我本以为他会迟到的。
Every day he left work at 4:45 p. m. on the dot.
每天下午4点45分他都毫不耽搁地离开公司。
Being on the dot for social functions is desirable.
对社交活动能够守时，是件令人喜欢的事。
Always remember that you are absolutely unique.
永远记住，你是独一无二的。