I wonder how i can make a question using verbs with prepositions especially when they are in passive voice.
For example, I have a sentence like below: An appointment is required for the service.
And I made this normal sentence into a question: For which service is an appointment required? I understand that this sentence is correct.
But, here i suddenly came up with one idea. Could you let me know if the sentence below is correct or not? If not, why is the sentence incorrect?
“Which service is an appointment required for?”