I am writing an essay and I am having trouble with the following sentence.<br/><br/>On this quest, I have already accomplished x, y, and z.<br/><br/>vs.<br/><br/>In this quest, I have already accomplished x, y, and z.<br/><br/>What is the correct word to use? What is the general rule, so that I don't find myself in this situation again.<br/><br/>Thanks!