as vs when — as needs an ongoing background (GiU Unit 116)
The frame
Section titled “The frame”✗ Everyone left the cinema as the film ended. → not OK
The film ended = point event. Two point events clash. Leaving was triggered by the ending → when:
✓ Everyone left when the film ended.
as = ongoing background only
Section titled “as = ongoing background only”as (time sense) needs a continuous verb — the main event lands inside the ongoing action:
- ✓ Everyone left as the film was ending
- ✓ As I was walking along the road, I saw a friend (Murphy)
- ✓ She burnt herself as she was cooking dinner
when = point events fine
Section titled “when = point events fine”- ✓ Everyone left when the film ended (trigger → action)
- ✓ When I got home, I made tea (sequence)
| as | when | |
|---|---|---|
| Background | ongoing (-ing) | event/point OK |
| Example | as I was walking | when I got home |
| JP mirror | 〜しているうちに | 〜したとき |
as’s other lives (all correct)
Section titled “as’s other lives (all correct)”- reason: As I was tired, I went to bed · As James speaks German, I asked him to translate (sentence-initial → capital As)
- comparison: as tall as me
- role: work as a teacher
Only the time sense demands ongoing. If the clause after as is simple-past event → switch to when.
Source
Section titled “Source”Raymond Murphy, English Grammar in Use, Unit 116 — as. Ebot lesson 2026-09-05.