So basically, whenever I see a word presented in two forms, like the example I first posted, I can just memorize all the meanings for the one word (I don't have to make separate flash cards for the plural and singular)?
memorize them as they are given. if the "special" meanigs are to you presented first, memorize so, later bother with the "normal". vice versa
You ought to treat them as separate words, because its just what they are. though it is true that these words "plural only" have their meanings related to the word of origin. it is no big deal, really.
Thanks for the help; I understand now. I have one more question: I read somewhere that it's best to learn foreign language vocabulary from context (by looking it up in the dictionary) after having learned one hundred words. How am I to do this if I'm studying from Wheelock's?