erst

He was erst a respected professor at the university.

用法提示：erst 作为副词，表示'以前'，修饰整个句子，说明过去的身份。

The castle, erst the home of a noble family, now lies in ruins.

用法提示：erst 作副词，描述城堡过去的用途，与 now 形成对比。

She was erst known as a brilliant pianist before her injury.

用法提示：erst 表示'曾经'，强调过去的状态或名声。