She became a professional mezzo-soprano.是什么意思？

She became a professional mezzo-soprano.

她成了一名专业的女中音歌手。

she

pron. 她，它；

例句
Her lover walked out on her after she had aborted their child.
她的情人在她打掉胎儿后甩了她。

became

v. 变为，成为（ become的过去式 ）；

例句
It became very clear that the incident was not just an aberration, it was not just a single incident.
事实已经很清楚，这件事不是偶发的，它并不是一起孤立的事件。

professional

adj. 专业的，专业性的，职业的；n. 专业人士；

例句
The whole cast executed the production with truly professional aplomb.
全体演职人员以一种真正的专业精神，从容不迫地开始了影片的制作。