illegal activities

基本解释

They bumped him off because he knew too much about their illegal activities.
他们把他谋杀了，因为他对他们的非法活动知道得太多了。
《新英汉大辞典》
Breaking into computers or computer networks and using them as a cover for serious illegal activities is a common activity, so common that many people have the skills necessary to do it.
侵入计算机和计算机网络并在其掩护下进行严重非法活动是一种非常普遍的行为，甚至普遍到许多人都具备实现此类行为的必备技能。
The Village Guards were set up in 1984 and have long been accused of involvement in illegal activities, says the BBC's David O'Byrne in Istanbul.
BBC的大卫在伊斯坦布尔报道说，“村庄护卫队”是在1984年成立起来的，长期以来都被人们称为是非法的活动组织。

For another,she pretended to be a woman who cleaned houses so she could report about illegal activities in employment agencies.
"You know my rule,Andy. In all illegal activities, we must obey the law, in every detail.
However,it charged several hundred whiskey producers and government officials with illegal activities.

It distances itself from illegal activities by offering to "coordinate" kidney, liver and lung transplants.
FORBES: Magazine Article

违法
In order to contain the procedural illegal activities, to safeguard human rights, our country should establish the pre-trial procedure decision rules system.
为了遏制程序性违法行为，保障人权，我国理应建立刑事审前程序性裁判制度。