Complete the sentence with the correct form of the verb in brackets: "She has never ____ (let) anyone read that notebook."

Բացատրություն

After has the verb takes its past participle, and this verb is invariant across all three slots, so the participle carries no ending. Letted does not exist in English. Note that spelling alone cannot show which slot is filled here — only the auxiliary reveals that this is a participle and not a past simple.