I am working through White's First Greek Book, and I have a problem. In Lesson VII, "Imperfect Indicative Active," the paradigm for this tense indicates that the suffix -ον plus the prefix ε serves to signal both the 3rd and 1st person. For each example, it gives the same conjugation for each verb in these cases. Same with the dual 2nd and 3rd person in the present indicative active: both have the suffix -ετον.
How am I to differentiate between these, with the exception of context? This site, which I have been using to check my answers, and which has usually been extremely faithful to what I produce, indicates that the correct translation of ηγον (circumflex and smooth breathing on η; I don't know how to type this in window) is "I was leading." But it appears that "they were leading" is also correct. On a simple translation exercise, where only the verb, without a context, is given, how do I differentiate between these two quantities and the dual in present indicative active?