How to makes this?
Why do I use the to after how?
closed as not a real question by FumbleFingers, Daniel, Mitch, RegDwigнt♦ Mar 21 '12 at 21:12
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Since I think your mother tongue is Italian, I expect your example sentence to be a calque of the equivalent italian expression, which uses the third person singular: "Come si fa questo?"
"Fa" is the third person singular of the verb "Fare" (to do/make). And that's why you say "makes".
I didn't find any references about why in English you'd require that, but keep in mind that not all languages work the same way, this is as true as it is obvious. So you can't just transpose a sentence from a language to another one using the exact same structure. Sometimes it works, yes, but the translation is almost never 1:1.
To make is a single unit called a full infinitive verb, of which the to is a necessary part.
How to makes this? is incorrect, since the make is indiscriminately pluralized (infinitives cannot be plural), and the question is a fragment.
You need more context for the sentence to be grammatical, and keep the infinitive verb in its singular form:
To keep it a question, you'll need to drop the infinitive (and the to) altogether: