Question

what is the passive voice of have you not visited Singapore​

Answer 1

Explanation:

DUDE IT IS A SENTENCE WITH AN INTRANSITIVE VERB. HENCE,IT CAN NOT BE CHANGED TO PASSIVE VOICE.

An intransitive verb is simply defined as a verb that does not take a direct object. That means there's no word in the sentence that tells who or what received the action of the verb.

Answer 2

Answer:

Has singapore not been visited by you?

Explanation:

In passive voice always the sentence starts with object, that means in place of subject we have to write object.

This sentence is yes-no type and negative assertive sentence that's why it's starts with auxiliary verb.

so the structure of interrogative(yes-no type) sentence of negative assertive is ,

auxiliary verb+object+not+been+ V3+complement+by+subject.