Future Time Clauses: When, Until, Before, After, and As Soon As

English often expresses future time without a future tense inside the time clause. The main clause can contain will, but the clause beginning with when, until, before, after or as soon as normally uses a present form.

Compare I’ll call you when I arrive, not when I will arrive. The future meaning comes from the whole sentence and the time conjunction; it does not need to be marked twice.

Separate the two jobs

The main clause gives the plan or result; the time clause gives the point that controls it: I’ll send the file as soon as I finish checking it. This fits the wider system of future forms.

Present perfect can look forward

Use present perfect when completion matters: Once I’ve read the report, I’ll respond. The form is present perfect, but the completed event is still future relative to now.

Do not turn this into a mechanical “never use will after when” rule. When will you arrive? is normal because when introduces a question, not a time clause. Function matters more than the word itself.