Future Time Clauses — When I do vs When I’ve done
when / after / before / until / as soon as / once / while / by the time
no will in the time clause
simultaneous vs completed action
What is a future time clause?
A time clause tells us when the main action happens. It’s introduced by when, after, before, until, as soon as, once, while, by the time, etc. Time clauses can come first or last in the sentence.
- Main later When I get home, I’ll call you.
- Main first I’ll call you when I get home.
Punctuation: If the time clause comes first, use a comma after it.
Golden rule
Don’t use future forms in the time clause.
- ✔ We’ll start when the team arrives.
- ✘ We’ll start when the team will arrive.
Linkers & typical patterns
| Linker | Clause form | Main clause (typical) | Meaning | Example |
|---|---|---|---|---|
| when | present simple/continuous/perfect | will + V / imperative / present | time point | Call me when you arrive. |
| as soon as / once | present simple/perfect | future or imperative | immediate sequence | We’ll text as soon as we’ve landed. |
| before / after | present simple/perfect | future | order of events | Finish your report before you leave. |
| until / till | present simple/perfect | often negative or with won’t | up to a limit | I won’t go until I’ve finished. |
| while | present continuous/simple | future/imperative | at the same time | Don’t interrupt while I’m speaking. |
| by the time | present simple/perfect | often will have + V-ed/3 (future perfect) | deadline before another future point | By the time you arrive, I’ll have finished. |
“When I do” vs “When I’ve done”
| Use | Choose | Meaning | Example |
|---|---|---|---|
| Two events happen at the same time (overlap) | present simple / continuous | the main action occurs during the time clause action | We’ll talk when we have dinner. (= during dinner) |
| The event in the time clause must be completed first | present perfect | the main action happens after completion | We’ll talk when we’ve had dinner. (= after dinner) |
| Completion is expected but not crucial to emphasise | either form | often little difference in meaning | I’ll move out when I find / when I’ve found a job. |
- Ambiguity I’ll call you when I have a shower can mean “during” or “after”. Prefer after I have a shower or when I’ve had a shower.
- Don’t use perfect for simultaneous actions ✘ When I’ve called Tom, I’ll invite him (during the call) → ✔ When I call Tom, I’ll invite him.
Other tense choices in the time clause
- Present continuous for ongoing future situations: When I’m working, don’t disturb me.
- Present perfect continuous to stress duration finishing before the main action: We’ll rest when we’ve been walking for two hours.
- Imperatives are common in the main clause: When you get home, call me.
Usage hints & common pitfalls
- No future in time clause: ✔ Once it stops, we’ll go. ✘ Once it will stop, we’ll go.
- Until with negatives: We won’t start until everyone arrives / has arrived.
- Comma rule: comma after an initial time clause; no comma if the time clause is last.
- Contrast with conditionals: If I win is uncertain; When I win assumes the event will happen.
Quick reference
| Goal | Best pattern | Model |
|---|---|---|
| Say two actions overlap | when/while + present (simple/cont.) | We’ll eat when we watch the match. |
| Say one action must finish first | when/after/once + present perfect | You’ll get dessert when you’ve finished. |
| Set a deadline point | by the time + present … / will have + V-ed | By the time you call, I’ll have left. |
Exercises:
Time Clauses: “When I do” vs “When I’ve done”
Choose the correct verb forms to complete the sentences below. Use the PRESENT PERFECT when possible.
1
When I
this email, I’ll join the meeting.
2
When the train
, we’ll set off for the hotel.
3
When you
the test, hand it in at the front.
4
When we
enough money, we’ll book the flights.
5
When the rain
, we’ll go out.
6
When I
home, I’ll message you.
7
When you
the brief, let me know your questions.
8
When the system
, try logging in again.
9
When she
her coffee, we can leave.
10
When water
100°C, it boils.
Time Clauses: “When I do” vs “When I’ve done”
Choose the correct verb forms for the gaps below. For some questions, you will need to choose TWO correct answers.
1
I’ll call you when I ____ home.
A.
B.
C.
2
When you’ve finished the exercise, ____ it in to your teacher.
A.
B.
C.
3
I’ll start cooking when ____ the ingredients. Choose TWO
A.
B.
C.
4
She usually reads when she ____ to bed.
A.
B.
C.
5
When ____ the car, we’ll go for a drive.
A.
B.
C.
6
Text me when you ____. Choose TWO
A.
B.
C.
7
I’ll lock up when everyone ____. Choose TWO
A.
B.
C.
8
When the meeting ____ , we can talk. Choose TWO
A.
B.
C.
9
I never watch TV when I ____ dinner.
A.
B.
C.
10
When you ____ your homework, we can play a game. Choose TWO
A.
B.
C.
Time Clauses: “When I do” vs “When I’ve done”
Fill in the gaps using the verb in brackets in either the present simple or present perfect tense. Use the PRESENT PERFECT when possible.
1
When you the report, send me the file. (finish)
2
I will call you when I home. (get)
3
When she her training, she will apply for the role. (complete)
4
We will leave when the rain . (stop)
5
I will text you when I everything. (pack)
6
You can borrow the laptop when I using it. (finish)
7
Start the presentation when the guests . (arrive)
8
Let me know when you from them. (hear)
9
I will print the tickets when I the confirmation email. (receive)
10
He will rejoin us when he from the flu. (recover)