A: Hello! This is Ben speaking.
B: Ben, this is Terry. Tomorrow night a party will be held in my apartment. I hope you can come.
A: Wonderful. I will arrive on the dot.
on the dot
dot是“点”的意思，on the dot字面意思就是“压着点的”，也就是“准时的，刚好在时间到的时候来的，不早也不晚的”。这个短语很实用，例如：约会，商务会议，确定日程等。
She was told to arrive at 8 o'clock on the dot.
She was very angry that he did not arrive on the dot; he had promised to.
The 3 o'clock train arrived on the dot.
She arrived at the airport at nine o'clock on the dot.
Ps：hold a party的意思是“举办晚会”，相当于have a party。再如：
I'd like to hold a party for her in my room.
They hold a party in celebration of their victory.