Complete the sentence with the correct form of the verb in brackets: "She insists that she has ____ (dream) about this house before."

Explication

Has requires the past participle, and here two of them exist side by side. Dreamt with -t is the older British spelling; dreamed with -ed is the more frequent form in American English writing and is fully at home in British writing as well, so the present perfect is correct with either. Leaving the verb unchanged would give the sentence no participle.