'Who do you go to the party with?'

The question comes from the statement form, i.e., the answer, by applying a series of transformations. The last step is the question form. The intermediate steps are not necessarily grammatical. There are only there to illustrate the process.

I spent my money on candy. < only one verb
I did spend my money on candy. < add a form of 'do'; change the main v

Thank you very much. I have another question in connection with it. Besides the fact I understand these transforms I'm not sure I could recognise it. What should I see in such a sentence to know that I have to use this transformations?

Is this any name of this grammar? I can't exactly explain what I think of but I can give an example for this. E.g. I can find rules on internet for 'condit

Hole One a New SeeWhat should I see in such a sentence to know that I have to use this transformations?

Hmmm. Maybe you are misunderstanding something. What I gave you is just a general way of forming any question. All questions have the same structure. It's not a matter of looking for sentences to transform, and I'm not advising you to go ab

Now I thought it over and it really makes sense. To tell the truth, I usually use (more exactly, it was some time ago) this fast on English courses, but those prepositions was strange to me. Now, as I see these transformations, I can grab the essence of it. I mean that, it result in a strange-looking sentence. I think, that was the problem. I have another problems. I open new posts for them.

Hole One a New Seebut those prepositions was were strange to me

So it's the prepositions at the end that bother you? I see.

Well, that's pretty characteristic of the English language. I don't think there are many other languages that have this structure or that use it so often.

If you want, tho

You got this book from David. -> Who did you get this book from?
He called you about the car repairs. -> What did he call you about?
The president of the company looks like Mr. Trump. -> How does the president of the company look like?
You are thinking of a chocolate cake. -> What are you thinking of?
We will have to rely on the custodian to open the door for us. ->

I tried to refer to that (with my poor English): these prepositions at the end give a strange-looking structure for these questions. In your last sentence, e.g., it is not strange to me, because the preposition doesn't stand alone at the end of the question. Of course it is only true, if I did these tasks (mainly the last one) correctly. But I think, you understand me.

Thanks for your he

Hole One a New SeeThe president of the company looks like Mr. Trump. -> How does the president of the company look like?

The instructions said to substitute Who or What. Where did you get How???

This is one of the most frequent mistakes made by learners of English, by the way! How

Hole One a New SeeIn your last sentence, e.g., it is not strange to me, because the preposition doesn't stand alone at the end of the question.

Right. The preposition is at the end of its clause instead of at the end of the whole sentence. We have a lot of this in English too.

Hole One a New SeeThanks for your help

You're

Thank you