I want to explain my confusing in a sentence:
"Do I have to obligate to do this?"
"Do I have to obligate doing this?"
Is there any difference between this sentence? First one I used "to do" and second one I used "doing".
So do they have same meaning? And can I also do this used for others verbs?
"To do" (infinitive) is better than "doing" (gerund) in this case. However, there are a few other changes: "Am I obligated to do this" would be the most natural use of "obligate." "Obligate" is something that happens to you, not something you do—"It rained, so I was obligated to use an umbrella"—the rain forced me to do something. Of course, you could have an even simpler sentence with "Do I have to do this?" since in English "have to" carries the meaning of being compelled.