Learn Arabic (Modern Standard): إياكم والشرارة؛ لقد اشتعلت المادة أثناء اللحام. - Beware of the spark; the material caught fire during the welding.

In the Arabic warning structure (أسلوب التحذير), this و does not function as a standard "and" joining two nouns. Instead, it acts as a structural link between the warned party (إياكم) and the danger (الشرارة). Grammatically, it implies two separate hidden verbs: "Save yourselves, and avoid the spark." In natural English, we just translate this whole phrase as "Beware of the spark."

What case ending does الشرارة take in this warning structure?

It takes the accusative case (منصوب), meaning it ends with a fatha (الشرارةَ). This is because the noun following the و is treated as the direct object of that hidden, implied verb meaning "avoid" or "beware of" (such as احذروا).

What is the purpose of using لقد before اشتعلت instead of just saying اشتعلت?

While اشتعلت alone means "caught fire," adding لقد before a past tense verb emphasizes the certainty or completion of the action. It serves as an intensifier ("indeed" or "already") and often maps well to the English present perfect tense, highlighting that the material "has caught fire" and that this is a relevant, established fact.

Why does اللحام (welding) take the genitive case (kasra) here?