Another thorn in my side is the use of the article — it’s not clear to me when you use it and when it’s dropped. Why does one say c’è vento (it’s windy), but c’è il sole (it’s sunny)? I struggle to understand the difference between uno stato d’animo (a state of mind) and una busta della spesa (a shopping bag), giorni di scirocco (days of sirocco) and la linea dell’orizzonte (the line of the horizon). I tend to make mistakes, putting the article when there’s no need (as in “Parliamo del cinema,” instead of di cinema, or “Sono venuta in Italia per cambiare la strada,” instead of cambiare strada; “We’re talking about the movies” instead of “about movies”; “I came to Italy to change the course” instead of “to change course”), but reading Elio Vittorini I learn that you say queste sono fandonie (those are lies). Thanks to an advertising poster on the street, I learn that il piacere non ha limiti (pleasure has no limits).
By the way: I’m still not very sure about the difference between limite and limitazione, funzione and funzionamento, modifica and modificazione (limit, function, change). Certain words that resemble each other torment me: schiacciare (crush) and scacciare (expel), spiccare (stand out) and spicciare (get something done quickly), fioco (weak) and fiocco (bow), crocchio (small group) and crocicchio (crossroads). I still mix up già (already) and appena (just). 
Sometimes I hesitate when I compare two things, and so my notebook is full of sentences like Di questo romanzo mi piace più la prima parte della seconda. Parlo l’inglese meglio dell’italiano. Preferisco Roma a New York. Piove più a Londra che a Palermo (I like the first part of this novel more than the second part. I speak English better than Italian. I prefer Rome to New York. It rains more in London than in Palermo).
I realize that it’s impossible to know a foreign language perfectly. For good reason, what confuses me most in Italian is when to use the imperfect and when the simple past. It should be fairly straightforward, but somehow, for me, it isn’t. When I have to choose between them, I don’t know which is right. I see the fork in the road and I slow down, feeling that I am about to come to a halt. I am filled with doubt; I panic. I don’t understand the difference instinctively. It’s as if I had a kind of temporal myopia.
Only in Rome, when I start speaking Italian every day, do I become aware of this problem. Listening to my friends, telling my Italian teacher something, I notice it. I say c’è stato scritto (there has been written) when one should say c’era scritto (there was written). I say, era difficile (it was difficult) when one should say è stato difficile (it has been difficult). I am confused above all by era (it was) and è stato (it has been) — two faces of the verb essere (to be), a verb that is fundamental. In Rome, for almost a year, my confusion torments me.
To help, my teacher provides some images: the background with respect to the main action. The frame with respect to the picture. A curving line rather than a straight one. A situation rather than a fact.
One says, la chiave era sul tavolo, the key was on the table. In this case a curving line, a situation. And yet to me it also seems a fact, the fact that the key was on the table.
One says, siamo stati bene, we have been comfortable. Here we have the straight line, a condition that savors of conclusiveness. And yet to me it also seems a situation.
The confusion makes me think of a certain geometric motif, a kind of optical illusion, that is found in the floors of churches, or old palazzi. It’s a series of squares in three colors, a simple but complex design that is deceptive to the eye. The effect of this illusion is astounding, disconcerting — the perspective shifts, so that you see two versions of the same thing, two possibilities, at the same time.
Searching for clues, I note that with the adverbs sempre (always) and mai (never) one often uses the simple past: Sono stata sempre confusa (I’ve always been confused), for example. Or, Non sono mai stata capace di assorbire questa cosa (I’ve never been able to grasp this thing). I think I’ve discovered an important key, maybe a rule. Then, reading È stato così (It Has Been Like That [The Dry Heart]), by Natalia Ginzburg — a novel whose title provides another example of this theme — I read, “Non mi diceva mai che era innamorato di me.… Francesca aveva sempre tante cose da raccontare … Aspettavo sempre la posta” (He never told me he was in love with me.…Francesca always had lots of stories to tell.… I was always waiting for the mail”). No rule, only more confusion.
One day, after reading Niente, più niente al mondo (Nothing, Nothing More in the World), a novel by Massimo Carlotto, I underline, like a lunatic, every use of the verb essere in the past. I write all the sentences in a notebook: “Sei stato dolce.” “C’era ancora la lira.” “È stato così fin da quando era giovane.” “Ero certa che tutto sarebbe cambiato in meglio.” (“You were sweet.” “The lira was still in use.” “He’s been like that since he was young.” “I was sure that everything would change for the better.”) But this labor turns out to be useless. I learn only one thing, in the end: it depends on the context, on the intention.
By now the difference between the imperfect and the simple past troubles me a little less. By now I know that one says, at the end of a dinner, È stata una bella serata (It’s been a lovely evening), but that it was (era) a lovely evening until it rained. I know that sono stata in Greece for a week, but that ero in Greece when I got sick. I understand that the imperfect refers to a sort of introduction — an open-ended action, without boundaries, without beginning or end. An action suspended rather than contained, confined to the past. I understand that the relationship between the imperfect and the simple past is a precise, complex system, to make time gone by more tangible, more vivid. A way of recounting something abstract, of perceiving something that isn’t there.