Because "a" would be difficult to distinguish since "andare" begins with the same vowel. Therefore "d" is added to form "ad"
Similar thing happens when you have "e" before a word that begins with a vowel (Donne ed uomini)
The prepositions A & DI are added after some verbs before the infinitive. Provare happens to be one of the verbs that uses A. Here's a good list you may like to use: http://italian.about.com/od/verbs/a/aa031908a.htm I believe the only way to really know these is to simply memorize them... Dnovinc gives a great explanation of why it is AD instead of A as well. Hope this helps. Cheers!
I don't understand what "a/ad" does in this sentence -- since andare is already "to go" and "to to go" doesn't make sense in English. Still, I will remember, "tries to go" uses "ad"
I think this is not because of "andare", but because of "prova". "Try to" is translated as "prova a/ad". "Andare", and other infinites, are translated just like "go" as infinitive.
Try to pronounce this sentence like an Italian person would in a normal conversation, that is rather fast. First with "a" then "with "ad". I presume you will notice that if you use "a" it is very difficult to distinguish the preposition "a" and the verb "andare".
why is wrong city here? I thought città was city. They put town instead of city
I think "in citta" probably translates to the English phrases/idioms "into town" or "into the city/town". Something like "into city" would sound strange to a native English speaker, but would be understood.
Every time I type the Italian word for city, Duolingo automatically changes the spelling to "citya" and I have to go back, delete the 'y' and type in a 't'. I have encountered other similar problems in the program.
If he can try going to the city why can't he practise going to the city ? Maybe someone can give me some clarity on this, please ?