Breakdown of Стоило пламени вспыхнуть, как дежурный схватил огнетушитель.
пламя
the flame
схватить
to grab
как
than (in 'no sooner ... than')
стоить
one had only to (as soon as)
Questions & Answers about Стоило пламени вспыхнуть, как дежурный схватил огнетушитель.
How does the стоило... как construction work in this sentence?
This structure translates to 'as soon as [A] happened, [B] happened'. The word стоило acts as an impersonal verb (always in the neuter past tense), so the logical subject of the first action (the flame) must take the dative case (пламени). This is followed by the infinitive вспыхнуть, and then как introduces the immediate result.
Why is the dative form of пламя spelled as пламени?
пламя (flame) is one of the special neuter nouns ending in -мя, just like время (time) and имя (name). When these words decline in any case other than nominative or accusative, their stem expands by adding -ен- before the ending. This makes the dative form пламени.
Could I use the imperfective verb вспыхивать instead of вспыхнуть here?
No, the стоило... как construction focuses on immediate, sequential events. Therefore, it generally requires perfective verbs for both the trigger action (вспыхнуть, meaning 'to completely flare up once') and the resulting action (схватил, meaning 'grabbed').
дежурный looks like an adjective, but it is acting as a noun here. How does it decline?