When the following word starts by a vowel sound, we use AN, e.g.: an elephant, an apple, an uncle, an hour, an honour, an heir, an heiress, an honourable man, an empty glass, an MP member, an L-shaped object, etc
When the following word starts by a consonant sound, including semivowels /j/ and /w/, we use A, e.g.: a house, a horse, a cat, a ghost, a friend, a European country, a ewe, a university, a universal language, a uniform, a UFO, a one-eyed person, a wet coat, a woman, etc.
Almost the same thing happens with the two pronunciations of the definitive article THE, e.g.: the ewe /ðə 'ju:/, the elephant / ði ‘ɛlɪfənt /.
And what about The United States, The United Nations, The United Kingdom, The European Commission, etc?
The audio is fine, I don't hear "la". If you have problems with audio just report it through in-lesson "report a problem" button, that way duolingo's staff gets notified.
Yes, you're right, since "ragazzo" = "boy" is masculine singular noun the definite article preceding it is "il" and because "mela"= "apple" is a feminine singular noun the indefinite article preceding it is "una".
- Generally, nouns ending in -o are masculine, nouns ending in -a are feminine.
- Nouns ending in -e may be masculine or feminine. The gender of these nouns must be memorized.
a bit more about this: http://italian.about.com/library/weekly/aa051000a.htm
Grammar rule. There are 3 masculine articles..."il" used before a masculine noun beginning with a consonant..ex. Il ragazzo, Il libro...."lo" used before a noun beginning with z (zio) or s + another consonant (stadio, spazio), ex. Lo stadio, lo zio) and "l'" followed by a noun beginning with a vowel...(uomo, uovo) ex. L'uomo, l'uovo). There are 2 feminine articles..."la" and l'......la casa.... article is followed by a feminine noun beginning with a consonant (casa)..la casa...and l' followed by feminine noun beginning with a vowel (Opera)...l'opera. make sense?? Good luck!!!