当时警察正在执行一项特别任务的翻译：Police are carrying out a special task 什么意思？中文翻译英文，英文翻译中文，怎么说？

青云英语翻译

The police are to perform a special task

Police are carrying out a special task

At that time the police were carrying out a special task

At that time, the police are carrying out a particular task

Police are carrying out a special task