准时：在特定的时间点上准确无误地。
正好：恰好在特定的时间点上。
just as it should be
同义词： precisely / exactly / on the nose / on the button
... corny陈词滥调, abercrombie，毫无新意 on the dot准时 potluck聚餐（各家带一道菜的聚餐方式） ...
once and for all 最后一次;干脆 on the dot 准时;正点 hit the spot (特指吃了食物, burberry sneakers，喝了饮料之后)精神完全恢复过来或感到满足;恢复精力;提精神 ..
... stick around 在邻近勾留或等候 on the dot 准时;误点 stick with 持续做, 常识！恐怕一条你都不晓得！（不转能行嘛？），保持 ...
展现自己骄人身姿,新开魔域私服发布站让步 on the dot 定时;误点 once and for all 最初一次;罗唆 ..
正点，准时地
The taxi showed up on the dot.
出租车准时到了。
Breakfast is served at 8 on the dot.
8点整开早饭。
They appeared on the dot of 9:50 p.m. as always.
他们同往常一样在晚上9点50分准时出现了。
And you can experience it all on the Internet at americanhistory-dot-s-i-dot-e-d-u.
VOA : special.2010.01.11
When the program is on your computer you say dot slash and this means on my computer.
当程序位于你的电脑上时，敲入,就意味着在我的电脑上运行。
计算机科学课程节选 : 哈佛公开课
So it's a little spot, a little dot on the map.
所以，它是个小地方，在地图上，它也只是一个小点。
SpeakingMax英语口语达人 : 和纽约的留学生
Employees are encouraged to behave like office drones, punching in at 9 and leaving at 5 on the dot.
We took the Williamsburg Bridge and arrived at 2:30 p.m. on the dot.
When the first day's doodle changed at midnight on the dot, she was captive in front of the computer to watch.