By the time
B2 Upper IntermediateThe conjunction 'by the time' is used to indicate that one event happens at or before the moment another event occurs. It typically requires specific tense pairings to show the sequence of events.
Overview
By the time functions as a subordinating conjunction that establishes a deadline or a chronological limit. It introduces a time clause that describes an event serving as the reference point for a second, earlier action. In the main clause, we use perfect tenses to emphasize that the action was already complete before that reference point.
Form
By the time + [event A], [event B (perfect tense)]
When referring to the past, the time clause uses the Past Simple and the main clause uses the Past Perfect. When referring to the future, the time clause uses the Present Simple and the main clause uses the Future Perfect.
Examples
Common mistakes
By the time he will arrive, the meeting will have finished.
By the time he arrives, the meeting will have finished.
In future time clauses, use the Present Simple after 'by the time', not 'will'.
By the time I got home, my family ate dinner.
By the time I got home, my family had eaten dinner.
The Past Perfect is necessary to show that dinner was finished before the arrival.
By the time vs. When
Use 'when' for consecutive actions and 'by the time' for actions with a completed result.
| Conjunction | Focus |
|---|---|
| When | Two events happening simultaneously or one immediately after another. |
| By the time | One event being already complete before the second event starts. |
Practice
By the time the police arrived, the thief ______ (escape).
Show answer
had escaped
Answer:had escaped
Why:The past perfect is used because the escape was completed before the police arrival.
By the time we ______ (get) to the station tomorrow, the train will have departed.
Show answer
get
Answer:get
Why:In future time clauses introduced by 'by the time', the present simple is used instead of the future tense.
I ______ (finish) the report by the time the manager asks for it.
Show answer
will have finished
Answer:will have finished
Why:The future perfect is used in the main clause to show completion before a future deadline.