Fill in the blank with the most suitable verb from the options given below:
____ you drink milk everyday?
The auxiliary verb, 'have' is used to form perfect tenses or used with an infinitive to express an obligation (Example: I have to be there). In the given sentence, the clause, 'They _____ not want to go' is in simple present tense form and not in the perfect tense. The main verb is 'drink' and it is not in infinitive form. There is no mention of obligation either. Hence, the auxiliary verb, 'have' cannot be used. The words, 'have' and 'has' are forms of the auxiliary verb, 'have'. Hence, both options C and D are incorrect.
The given sentence is an interrogative in the present tense. In such cases, the auxiliary verb, 'do' is used. Hence, the answer is either 'do' or 'does'. If the subject is in the third person, singular form, the auxiliary verb, 'does' is used. Otherwise, 'do' is used. Here the subject is 'you', is in the second person. Hence, option A is the correct answer and option B is incorrect.