أَنَّا صَبَبْنَا ٱلْمَآءَ صَبًّا
Sentence structure
أَنَّا begins an emphatic clause whose exact attachment has two recognized analyses. صَبَبْنَا is its verbal predicate; ٱلْمَآءَ is the object and صَبًّا an emphatic cognate accusative.
Ayah summary
Allah poured down water abundantly.
أَنَّا — That [We]
Grammar: أَنَّ is an accusative/emphatic particle; attached نَا is the first-person plural pronoun functioning as its noun.
صَبَبْنَا — [We] poured
Grammar: first-person plural perfect verb; it functions as the خبر أن. Attached نَا is a first-person plural pronoun functioning as the subject.
ٱلْمَآءَ — the water
Grammar: ٱلْ is the definite article. accusative noun functioning as the object.
صَبًّۭا — (in) abundance
Grammar: accusative noun functioning as the cognate accusative.