Final answer:
Cdk inhibitors regulate Cdks by preventing their full activation until a specific cell cycle event is completed.
Step-by-step explanation:
Molecules that prevent the full activation of Cdks are called Cdk inhibitors. Many of these inhibitor molecules directly or indirectly monitor a particular cell cycle event. The block placed on Cdks by inhibitor molecules will not be removed until the specific event that the inhibitor monitors is completed.