Complete the sentence with the correct form of the verb in brackets: "By the time we noticed, the paint had ____ (spill) across the floor."

Explication

Had introduces a past participle, and both forms of this verb are standard. The -t spelling survives strongly in the fixed saying about crying over spilt milk, while the -ed spelling is the ordinary form in American English and the more common one in current British writing. Either of them finishes the past perfect correctly.