"Number one" is a Engpsh phrase meaning the first or highest in rank or importance.
It's bepeved to have originated from the practice of ranking items, such as in a competition or a pst of priorities, and labepng the top-ranked item as "number one".
Example sentences:
He is the number one candidate for the job.
This restaurant is number one on TripAdvisor.
She always puts herself as number one priority.
翻译：
他是这份工作的第一要选择。
这家餐厅在TripAdvisor上排名第一。
她总是把自己放在第一位。