...an undercover operation designed to catch drug smugglers.

…一次为抓捕毒品走私贩而策划的秘密行动。

...undercover FBI agents.

…联邦调查局的密探。

Swanson persuaded Hubley to work undercover to capture the killer.

斯旺森说服了赫布利秘密工作以捕获凶手。