It staged a major uprising in 1966, followed by years of underground activities.

Arrested in 1929, he continued underground political activities while imprisoned.

The purpose of the robbery was to get funds for underground activities.

He runs most of the Hollows' illegal and underground activities.

Yet he continued his underground activities for another ten years.

That is especially true by historical standards, because the amount of underground economic activity has been expanding so much.

Zhen was no doubt the leader of all this underground activity.

Performance enhancement is like any other kind of underground activity: the participants are the only ones who know for sure what they're up to.

The book includes special game rules for underground activities, including combat, travel, and mining.

After the capitulation of the capital, he left the city together with the civil population and continued his underground activities.