אבן עזרא — ויאמר אלהים יקוו המים / וירא אלהים כי טוב

Q — Day 3 of creation has "וירא אלהים כי טוב" twice (verses 10 and 12), while day 2 has none. Rashi (citing Chazal) resolves this by saying day 2's work — separating the waters — wasn't completed until day 3, so the first "כי טוב" of day 3 marks the closure of day 2's project.

A — Ibn Ezra rewrites the whole structure via a single grammatical move. The וי"ו in "ויאמר אלהים יקוו המים" (verse 9) is past-perfect — "and God had ALREADY said" — and "יש כמוהו בתורה למאות." So verses 9-10 describe what was already done on day 2 (when both ארץ and שמים were made together — proven from "ביום עשות ד' אלקים ארץ ושמים"), and the "וירא אלהים כי טוב" of verse 10 belongs to day 2's account, not day 3. Day 3 itself has just one "כי טוב" (verse 12), like every other day. The bigger move: a grammatical principle (וי"ו = past perfect) dissolves a textual puzzle that Chazal needed an extra-textual frame to resolve.