Final answer:
The conjugation of the Spanish verb 'mentir' in the subjunctive 'tu' form is 'mientas'.
Step-by-step explanation:
The verb mentir means 'to lie' in Spanish. In the subjunctive mood, which is used to express various states of unreality such as doubt, possibility, necessity, or action that has not yet occurred, we need certain specific conjugations. For the 'tu' form, or the second person singular, the conjugation of mentir in the subjunctive is 'mientas'.
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