Time Clauses

A time clause tells you when something happens. It is introduced by a time conjunction — words like when, before, after, until, as soon as, while, once, and by the time. Time clauses combine with a main clause to form a complete sentence.

The Golden Rule: No "will" in time clauses

When a time clause refers to the future, use the present simple (or present perfect) — never will. The main clause keeps will for the future, but the time clause does not.

❌ Incorrect	✅ Correct	Rule
I'll call you when I will get* home.*	I'll call you when I get* home.*	Present simple in the time clause
We'll wait until the rain will stop.	We'll wait until the rain stops.	Present simple in the time clause
She'll email us after she will arrive.	She'll email us after she arrives.	Present simple in the time clause

This rule applies to all time conjunctions: when, before, after, until, till, as soon as, once, by the time, while. It also applies to if and unless in conditional sentences.

This lesson covers three time frames — future, past, and general — across A2 to B2 level.

Future Time Clauses: Present Simple After Time Conjunctions

When you talk about the future using a time clause, follow this pattern:

Main clause (will / can / imperative) + time conjunction + present simple

The time clause can also come first:

Time conjunction + present simple, + main clause (will / can / imperative)

The 6 Key Time Conjunctions

Conjunction	Meaning	Example
when	at the time that	I'll call you when* I get home.*
before	earlier than	Close the windows before* you leave.*
after	later than	She can watch TV after* she finishes her homework.*
until / till	up to the time that	We'll wait here until* the rain stops.*
as soon as	immediately when	I'll text you as soon as* I arrive.*
while	during the time that	I'll read my book while* I wait for the bus.*

Identifying the Main Clause vs Time Clause

The key to getting the tense right is knowing which clause is which:

Part	Uses	Example
Main clause	will, can, going to, imperative	I'll call you… / Close the windows…
Time clause	present simple (NOT will)	…when I get* home.* / …before you leave.

💡 "When" vs "if": Use when if the event is certain to happen (When you get to the hotel… — you're definitely going). Use if if the event is uncertain (If it rains tomorrow… — it might not rain).

👉 Practice Future Time Clauses →

Advanced Future Patterns: By the Time, Once & Present Perfect

By the Time & Once

Two more time conjunctions follow the same golden rule:

Conjunction	Meaning	Example
by the time	before or at the moment that	By the time we get there, the shop will be closed.
once	as soon as / after	Once you understand the rules, the game is easy.

"By the time" + future perfect: The main clause often uses future perfect (will have + past participle) to show an action will be complete:

By the time you get home, I will have finished cooking.

Present Perfect in Time Clauses

You can use present perfect (instead of present simple) in a time clause to emphasise that an action will be fully completed before the main clause action:

Present simple	Present perfect	Difference
I'll lend you the book after I finish* it.*	I'll lend you the book after I have finished* it.*	Present perfect emphasises completion
She'll email us once she arrives.	She'll email us once she has arrived.	Emphasises arrival is fully done

Both are correct. Present perfect adds emphasis on completion.

⚠️ The Time Clause vs Noun Clause Trap

This is one of the trickiest distinctions at B1 level. The word when can introduce two different types of clause — and the tense rule is opposite:

Type	Rule	Example
Time clause (= at the time that)	Present simple	Call me when* she comes back.*
Noun clause (= indirect question)	Will for future	I don't know when* she will come back.*

How to tell the difference:

If "when" answers the question "At what time will the main clause happen?" → time clause → present simple
If "when" is the object of a verb like know, wonder, ask, tell → noun clause (indirect question) → use will

Time clause	Noun clause
She'll tell us when* she's ready.* (= at the time she's ready)	We don't know when* she will be ready.* (= the question is "when?")
We'll evacuate when* the alarm sounds.*	Nobody knows when* the alarm will sound.*

👉 Practice Advanced Future Time Clauses →

Past Time Clauses

When talking about the past, time clauses use past tenses — past simple, past continuous, or past perfect — depending on the relationship between the events.

When + Past Simple: Interruption or Sequence

When + past simple describes a short completed action — often one that interrupts a longer action or starts a sequence:

When I got home, my family was having dinner. (interrupted an ongoing action)
When she opened the door, she noticed that someone had broken in. (one event, then another)

While + Past Continuous: Simultaneous Actions

While + past continuous describes an action in progress at the same time as another:

While the children were playing, their parents prepared dinner.
While she was cooking, he was setting the table. (two simultaneous ongoing actions)

Before / After + Past Perfect: Sequencing Events

Use past perfect (had + past participle) to show which event happened first:

Pattern	Example	Sequence
Past perfect + before + past simple	He had packed* his bags before the taxi arrived.*	Packing first, then taxi
After + past perfect + past simple	After the guests had gone, we started* cleaning.*	Guests left first, then cleaning
By the time + past simple, + past perfect	By the time we arrived, the film had started.	Film started first, then we arrived

When past perfect is optional: If the sequence is already clear from context (especially with before and after), past simple can be used in both clauses:

After he graduated, he found a job. ✅ (sequence is clear from "after")

Until / As soon as in Past Contexts

Until + past simple / past perfect: She didn't say anything until everyone had left.
As soon as + past simple: As soon as the bell rang, the students rushed out.

👉 Practice Past Time Clauses →

Mixed Patterns and Advanced Structures

Whenever / Every Time: Habitual Time Clauses

Whenever and every time describe actions that happen repeatedly. Both clauses use the same tense:

Time frame	Example
Present habit	Whenever I hear* that song, I think of my childhood.*
Past habit	Every time he kicked* the ball, the crowd cheered.*

Hardly … When / No Sooner … Than

These advanced structures describe two events happening in very quick succession in the past. They use past perfect + past simple with inverted word order:

Pattern	Structure	Example
Hardly … when	Hardly + had + subject + past participle … when + past simple	Hardly had* she sat down when the phone rang.*
No sooner … than	No sooner + had + subject + past participle … than + past simple	No sooner had* I closed my eyes than the alarm went off.*
Barely … when	Barely + had + subject + past participle … when + past simple	I had barely finished speaking when* he started arguing.*

⚠️ Don't mix up the pairs: Hardly pairs with when. No sooner pairs with than. Never write ~~hardly … than~~ or ~~no sooner … when~~.

Other Time Expressions as Conjunctions

Expression	Meaning	Example
the moment	at the exact instant	The moment she heard* the news, she burst into tears.*
the instant	= the moment	The instant the door opened, the dog ran out.
just as	at the exact same time	Just as I was leaving, the phone rang.

Before + -ing (Reduced Time Clause)

When the subject of both clauses is the same, before/after can be followed by -ing instead of a full clause:

She locked the windows before leaving the house. (= before she left)
After finishing dinner, we went for a walk. (= after we finished)

👉 Practice Mixed Time Clauses →

Common Mistakes to Avoid

Incorrect	Correct	Explanation
I'll call you when I will get* home.*	I'll call you when I get* home.*	No will in future time clauses — use present simple
I don't know when she comes* back.* (noun clause)	I don't know when she will come* back.*	Noun clauses (indirect questions) DO use will
Hardly had she sat down than* the phone rang.*	Hardly had she sat down when* the phone rang.*	Hardly pairs with when, not than
By the time we arrived, the film started.	By the time we arrived, the film had started.	By the time + past simple needs past perfect in the main clause
While I drove* to work, I saw a rainbow.*	While I was driving* to work, I saw a rainbow.*	While + past continuous for an action in progress
No sooner had I left when* it started raining.*	No sooner had I left than* it started raining.*	No sooner pairs with than, not when

Quick Summary

The Golden Rule by Time Frame

Time frame	Time clause tense	Main clause tense	Example
Future	Present simple (or present perfect)	will / can / imperative	When I get* home, I'll call you.*
Past	Past simple / past continuous / past perfect	Past simple / past perfect	When I got* home, my family was having dinner.*
General/habitual	Present simple	Present simple	Whenever I hear* that song, I think of home.*

Time Conjunction Quick Reference

Conjunction	Meaning	Pairs with
when	at the time that	—
before	earlier than	—
after	later than	—
until / till	up to the time that	negative main clause (won't … until)
as soon as	immediately when	—
while	during the time that	continuous tense
by the time	before a certain moment	future perfect / past perfect
once	as soon as / after	—
whenever	every time that	present simple (habitual)
hardly … when	very quickly after (formal)	past perfect + inversion
no sooner … than	very quickly after (formal)	past perfect + inversion

Practice Tips

The #1 rule to memorise: no "will" after time conjunctions. This is the single most tested grammar point for time clauses. When you see when, before, after, until, as soon as in a sentence about the future, use present simple in that clause.
To tell time clauses from noun clauses, look at the main verb. If the verb before "when" is know, wonder, ask, tell, decide — it's a noun clause (indirect question) and DOES use will. If the main clause describes what will happen AT that time — it's a time clause (no will).
For past time clauses, match the pattern to the relationship. Short action during a longer one? When + past simple / while + past continuous. Sequence of events? Past perfect for the first event. Quick succession? As soon as + past simple.
Remember the pairs: "hardly … when" and "no sooner … than". These are fixed combinations. Write them as formulae and practise them as pairs.
Use present perfect in time clauses to stress completion. After I finish (normal) vs After I have finished (emphasises fully done). Both are correct, but present perfect is more precise when completion matters.

Practice All Exercises

Ready to practise time clauses? These time clauses exercises online — with answers and explanations for every question — cover A2 to B2 level. Printable time clauses PDF worksheets are also available for offline study. Work through all four sets: future time clauses exercises at A2 with when, before, after, until and as soon as; advanced future patterns with by the time, once, unless and present perfect in the main clause and time clause (B1); past time clauses with past simple, past continuous and past perfect (B1); and a B2 mixed time clauses set including whenever, hardly … when, no sooner … than, and all tenses combined:

Set	Topic	Level
Set 1	Future Time Clauses: Present Simple after When, Before, After & Until	A2
Set 2	Future Time Clauses: By the Time, Once & Present Perfect	B1
Set 3	Past Time Clauses: When, After, Before & While	B1
Set 4	Mixed Time Clauses: All Tenses & Conjunctions	B2

Now try the exercises to practise what you've learned!

Learn Time Clauses