French Contractions and Genders
How am I supposed to know the gender of a word if all I see is it's contraction? Some might be easily discerned, like l'homme being le + homme, but am I supposed to assume that when the vowel it's proceeded by is an A for instance, that it's feminine, like l'assiette? And what about other vowels that make the word a contraction, like l'usine?
You can often tell if a word is masculine or feminine by looking at the ending. (The beginning of a word doesn't have much to do with its gender as far as I know...) Most things that end in e, especially formations like -ette, -enne, -ère, -euse, and -ine, are feminine, as are most words that end in -tion. Words that end in a consonant are more likely than not masculine, but with a lot of exceptions. And you can always find out for sure by looking the word up in a dictionary. It's really something that Duolingo should add to the built-in dictionary, but in the meantime try here http://www.larousse.com/en/ or here http://dictionnaire.reverso.net/ (It'll say nm for masculine noun or nf for feminine noun.)
I agree with anomalocaris. The endings give a good clue, but with plenty of exceptions. For some words it kind of makes sense that they are masculine or feminine, while for others there seems now rhyme or reason to it. And some words can be both of course, and may or may not have different spellings, as in "un enfant" and "une enfant". It's important to try to memorize the gender of nouns along with the word itself, and I find it helpful to use un/une to practice vocab for words beginning with a vowel (rather than le/la).