Event where the number 12 is important, and a feature of 12 two-word answers in this puzzle

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Similar Crossword Questions:

Number of times this puzzle's theme word appears diagonally in the grid (to complete the puzzle, shade those words plus the Down answers that begin where they meet)
Word needed to be added to 12 appropriately placed answers in this puzzle for their clues to make sense
Final (and a word that can precede the first word of this puzzle's longest answers)
Word separated in this puzzle's six longest answers
The word, as suggested by the saying formed by the ends of this puzzle's four longest answers
Number of times the letter 'U' appears in each of this puzzle's eight longest answers
Discussion group, and a word that can follow the ends of this puzzle's five longest answers
Feature of this puzzle's theme answers?
Word that can follow the starts of this puzzle's five longest answers
European acme, and word hiding in this puzzle's 5 longest answers
Zamboni-prepared surface, and word that can follow the last word of the puzzle's four longest answers
Driveway stuff (and word that's hidden in this puzzle's four longest answers)
Number of protons by which the elements in the four longest puzzle answers have been enhanced
Word that can precede the first word of the six longest puzzle answers
Word divided in this puzzle's nine longest answers
It can follow the last word of this puzzle's five longest answers
Important trial figure, or what you'll be when you read this puzzle's other four longest answers
Word that can precede each set of circled letters, forming a literal hint for entering certain answers in this puzzle
Word that can follow the first word of this puzzle's four longest answers
Wee hr., and a hint to a feature common to this puzzle's four longest answers
Word hidden in this puzzle's longest answers
Feature of six other long answers in this puzzle
Word "split" in this puzzle's eight longest answers
Govern, or word that can follow the first word of the four longest puzzle answers
Picnic serving, and when divided properly, a hint to a hidden feature of six pairs of puzzle answers