Final answer:
To complete the sentence, use 'Tu fais un gâchis,' which means 'You make a mess.'
Step-by-step explanation:
To complete the sentence using the correct form of the verb 'faire,' you would say 'Tu fais un gâchis.'
'Fais' is the second person singular form of the verb 'faire' in the present tense. It means 'do' or 'make,' so the sentence translates to 'You make a mess.'
Here, 'tu' is the subject pronoun used to refer to the second person singular, which is 'you' in English. The verb 'faire' is conjugated to match this subject pronoun.
Learn more about Using the verb 'faire' in a sentence