Listening to Natalia Worthington's "A Spoonful of Russian" lesson 3, I noticed that in the phrase "ничего хорошего" Natalia pronounces both "г"'s as "в". Likewise, in the song "Подмосквные вечера", it sounds to my ears as though the singer pronounces the word "лунного" with a "в" sound rather than a "г" sound.
I read in the New Penguin Russian Course that some other words also have "г" that sounds like "в" (его, сегодня). I notice that in all these cases, the "г" in question is directly before an "o". Is "го" always pronounced "во" or only sometimes? Is there a way to predict when "г" will sound like "в"?
Sorry if this is a stupid question, I'm only just beginning to learn Russian.