When, While, Before & After
Two actions, one timeline: when and while join actions happening at the same time; before and after put one action in front of the other. Tiny words, perfect timing.
Time Conjunctions
Join actions on a timeline
A time conjunction joins two actions and tells you their order: when/while = at the same time, before = earlier, after = later. Flip the two parts and the meaning stays the same.
When — at that moment
one thing happens, the other tooWhen I got home, I cooked dinner
While — during
two things together, one long actionShe listened to music while she cooked
Before — earlier
first this, then thatI brush my teeth before I go to bed
After — later
this, then thatWe watched a movie after we ate
⚠️ Flip the parts and the meaning stays: I cooked dinner when I got home.
The Formula
Two actions, one joiner
Each conjunction is the bridge between two clauses. The order can flip freely — the joiner always sits between the two actions.
⚠️ Clause + conjunction + clause. Change the order, keep the meaning.
The Comma Rule
Time first, comma next
When the time clause comes first, add a comma after it. When it comes second, no comma is needed. One rule, no exceptions.
Time clause first
comma after the first clause
Before I go to bed, I brush my teeth
Time clause second
no comma needed
I brush my teeth before I go to bed
⚠️ Time first → comma. Time second → no comma. That is the whole rule.
Common Mistakes
Three timing slips
The mistakes come from treating the conjunction like a full stop, or from forgetting that the tenses on both sides should match the moment.
After eat dinner, we walked.
After we ate dinner, we walked.
💡 After joins a full clause (after we ate) — not a bare verb.
When I was young, I play football.
When I was young, I played football.
💡 Both sides of when should agree: past context, past verb.
I will call you before I will leave.
I will call you before I leave.
💡 After before, the present does the future job — no will.
Quick Quiz
Test what you just learned
Three minutes, five questions — check what stuck. No essay questions, we promise.
I always drink coffee ___ I go to work.
💡 Extra info1 sections
Two Timing Teams
Same moment, or one after another
All time conjunctions do one of two jobs: they join actions at the same moment, or they line them up one after the other.