Future Time Clauses — English But Better

The key rule Conjunctions Clause order Exercises

The key rule: NO will in the time clause

In sentences about the future, the time clause (the part with when, as soon as, until, etc.) uses the present simple — NOT "will". The main clause uses will/going to.

✓ Correct:
"I'll call you when I arrive." (present simple in time clause)

✗ Incorrect:
"I'll call you when I will arrive."

Why? The time clause describes the condition under which the main action will happen. English treats this condition as certain, so it uses present simple — even though the meaning is future.

Common conjunctions

Conjunction	Meaning	Example
when	at the moment that	When I finish work, I'll go to the gym.
as soon as	immediately after	As soon as she arrives, we'll start.
before	earlier than	Finish your homework before* you go out.*
after	later than	After you eat, take this medicine.
until / till	up to the moment that	Wait here until* I come back.*
once	as soon as / now that	Once you understand the rule, it's easy.
by the time	before a certain point	By the time you read this, I'll have left.

if vs when: Both take present simple for future meaning. "If" = a condition that may or may not happen. "When" = you're certain it will happen: "If it rains, we'll cancel." vs "When it gets dark, we'll go home."

Clause order

The time clause can come before or after the main clause. When it comes first, use a comma.

Order	Example
Main clause first (no comma needed)	I'll tell her when I see her.
Time clause first (use a comma)	When I see her, I'll tell her.

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