A time-driven control is defined as a monitoring system that is based on a fixed time interval, such as weekly or monthly progress reports. The expected frequency of progress reports specified in a work package represents a time-driven control, where updates are required at predefined intervals irrespective of the state of the project at those times.References: = PRINCE2 7 Foundation handbook and online resources

Reference:
http://prince2.wiki/Continued_business_justification

A risk event in PRINCE2 is described as the area of uncertainty in terms of the threat or opportunity. It specifically refers to a specific set of circumstances that may occur and impact the project if the risk materializes. This description encapsulates the nature of a risk as being either a potential threat or an opportunity based on uncertain events that might affect project objectives.References: PRINCE2 7 Foundation handbook and official documents.