وَإِذَا ٱلْمَوْءُۥدَةُ سُئِلَتْ
Sentence structure
The girl buried alive is nominative in this construction, and سُئِلَتْ states the passive question asked of her.
Ayah summary
The innocent girl who was buried alive will be questioned.
وَإِذَا — And when
Grammar: وَ coordinates the whole conditional construction with the preceding one. إِذَا is a future non-jussive temporal adverb containing conditional meaning.
ٱلْمَوْءُۥدَةُ — the female infant buried alive
Grammar: The noun is nominative; here it is the deputy subject of an omitted passive verb explained by سُئِلَتْ.
سُئِلَتْ — is asked
Grammar: A feminine singular perfect passive verb. The written verbal clause is explanatory and has no syntactic position.