English — present tense in future time clauses
When a clause introduced by when, as soon as, before, after, until or if refers to the future, English uses the present simple, not will. The main clause keeps will: I'll call you when I arrive.
How it works
Use the present simple after the time/condition conjunction, and will in the main clause: I'll wait until she comes back; We'll leave as soon as the taxi arrives; Call me before you go. The future meaning is carried by the main clause, so the subordinate verb stays present.
Examples
| Conjunction | Example sentence |
|---|---|
| when | I'll call you when I arrive. |
| as soon as | We'll start as soon as everyone is here. |
| before | Finish your homework before you go out. |
| after | I'll email you after I speak to the manager. |
| until | Wait here until the rain stops. |
| if | If it rains tomorrow, we'll stay at home. |
| by the time | By the time you get there, the show will have started. |
Good to know
A very common mistake is putting will in the time clause: not I'll call you when I will arrive, but I'll call you when I arrive. Note that if and when can also introduce indirect questions, where will is allowed because they are not time clauses: I don't know when he will arrive; I'll ask if she will come. For events before the future action, use the present perfect: I'll leave after I've finished.