This illegal activity was once commonplace.

这种非法活动曾一度流行。

This business is a cover for illegal activity.

表面上这是家商行，实质上从事非法活动。

Use the site in any way to advocate illegal activity.

使用网站以任何方式宣扬非法活动。

One does not have to support illegal activity in order to defend intrusive reporting.

为侵扰性报道辩护的人，并不就是支持非法活动。

Clark was a prime target of a Congressional investigation into this illegal activity.

克拉克成为了美国国会调查非法活动的主要目标。