I don't know why "The weasel captures the mouse is not allowed." My Latin dictionary (Casell's) gives the meaning of capto as "to seize, catch at, lay hold of, or hunt. While the idea of pursuit is included, the idea of actually catching the prey is also included. Why do we always have to assume the weasel fails?
Lewis & Short's long entry suggests that the notion of attempting to catch predominates, but that the word can sometimes mean grab hold of. In addiiton, the verb is a frequentative from
capio' and frequentatives normally denote repeated, regular action, not attempted action. accordingly, i doubt whethercapto' is a good word for inclusion in a course for beginners.