Several men a block away, by the sound, startled into sudden activity.

There was sudden activity in the street that caused them all to turn hurriedly.

She glanced around, was immediately aware of the sudden activity.

They happen because of sudden, abnormal electrical activity in the brain.

Worse, he had just seen sudden activity on this side of the warship.

With all this sudden economic activity, cash is at a premium.

They watched for a while but could not distinguish the cause of the sudden activity.

There was a sudden violent activity beside her, and she turned to see him partially sitting up.

She was about to wake him when sudden activity below startled her.

The sudden activity suggested something was to be happening soon.