Put the verb in brackets into the Present Perfect form. I (tell) the truth.

The correct answer is 'have told'. Explanation: In the Present Perfect tense, the verb 'have' or 'has' is used as an auxiliary verb, followed by the past participle of the main verb. For the pronoun 'I', we use 'have'. The past participle of 'tell' is 'told'. Therefore, the correct form is 'have told'. So, the sentence becomes: I have told the truth.