It ought to be Number One.

它应该是第一条。

You have to be number one.

把自己放在首位。

I want to be number one.

我想做第一名。

How soon is China going to be number one?

二是中国是否很快会成为世界第一？

Brian competed with Colin to be number one in class.

布赖恩和科林比赛要得到班上的第一名。