Question

Fill in the blank with the correct auxiliary verb from the choices given.
You _________ not use somebody else's towel and toothbrush.

• A. Are
• B. Have
• C. Ought to
• D. Must

Answer 1

The correct option is D Must

Option A: The phrase, 'Subject + are" is usually followed by a verb in present continuous form (i.e verb+ing). However, in the given sentence, the verb, 'use' is in simple present tense. Alternately, the phrase, 'Subject + are" is followed by 'to+ verb in simple present tense'. Eg: 'You are not to use somebody else's towel and toothbrush'. However, in the given sentence, the preposition 'to' is not used. Hence, the auxiliary, 'are' is inappropriate. Option A is incorrect.

Option B: The auxiliary, 'have' is used in the formation of the perfect tenses, along with the verb in past participle form. The past participle form of the verb, 'use' is 'used'. However, in the given sentence the simple present tense form of the verb is used. Hence, this auxiliary is not appropriate and option B is incorrect.

Option C: The auxiliary, 'ought' is used to express an advice/ an obligation. In negative sentences, the auxiliary, 'ought' is followed by not and then the preposition 'to'. The format of usage is: Subject + ought not + to + verb in simple present tense. However, in the given sentence, the preposition 'to' is not used. Hence, the auxiliary, 'ought' is inappropriate. Option C is incorrect.

Option D: The auxiliary, 'must' is used to express a command/ advice/ an obligation. In the given sentence, the speaker is advising the listener not to use somebody else's towel and toothbrush. Hence, this auxiliary is appropriate to fill the blank. Option D is correct.