“By” and “until” are both time-related prepositions that indicate boundaries or limits within which actions or events occur. The main difference between the two lies in their implications regarding timing and completion of actions.

“By” typically indicates a deadline or point in time before which something should be completed. It implies that the action should be done no later than the specified time. For example, if a project is due “by Friday,” it means it must be completed on or before Friday.

On the other hand, “until” denotes the continuation of an action or event up to a specified point in time. It signifies that the action will persist or be in effect until the indicated time is reached. For instance, if a store is open “until 9 p.m.,” it means it will remain open and serve customers until 9 p.m.

In terms of expressing time boundaries and expectations, “by” sets a clear deadline by which something must be accomplished, creating a sense of urgency or finality. It provides a specific time frame within which the action should be completed, leading to a more definite expectation.

Meanwhile, “until” conveys a sense of duration, indicating how long an action will continue or be valid. It establishes a time span during which the activity persists, emphasizing the ongoing nature of the process until the designated end point is reached.

In different contexts, the choice between “by” and “until” can significantly impact the understanding of time-related instructions or expectations. Therefore