ad. 以前, 往昔的

[ adv ]
at a previous time
<adv.all>
at one time he loved herher erstwhile writing
she was a dancer once

Erst \Erst\ ([~e]rst), adv. [Orig. superlative of ere; AS.
[=ae]rest. See {Ere}.] [Archaic]
1. First. --Chaucer.

2. Previously; before; formerly; heretofore. --Chaucer.

Tityrus, with whose style he had erst disclaimed all
ambition to match his pastoral pipe. --A. W. Ward.

{At erst}, at first; at the beginning.

{Now at erst}, at this present time. --Chaucer.