"Al gatto piace il cane."
This caught me out too...
"In Italian Jane likes John becomes John piace a Jane. The sentence structure is reversed, and the conjugation of piacere reflects what is liked, not who is doing the liking. Other verbs such as mancare (to miss) work the same way."
I don't understand this piece of grammar is about now.
I was confused by many different uses of piacere in Duolingo and this helped me understand: http://www.rocketlanguages.com/your-community/italian-vocab/mi-piace-ti-piace-ci-piace-etc
As long as you always translate "piace" as "is pleasing" then the rest should fall into place. "Al" is "To the", so "To the cat, the dog is pleasing". You could also write it as "Il cane piace al gatto" which is "The dog is pleasing to the cat" if that's easier to understand, though it's not how someone would usually say it, as far as I know.
As for determining when it takes this form, you just learn. Certain words are just like this.
Agreed. Otherwise how can you tell who likes who, if you don't put "al"?
http://italian.about.com/od/verbs/a/italian-verb-piacere.htm (sometimes no "a" because with a+pronoun -> particella pronominale)
I'm still confused-- where everyone seems to think "to the cat the dog is pleasing" is the literal translation, in the little 'helper' duolingo window it introduces "John piace a Jane" to mean Jane likes John. The subjects are reversed.
Are the subjects in "al gatto piace il cane," not replaced in the translation, then? Why isn't it "the dog likes the cat" in English?
Notice that in their example "John piace a Jane", the "a" is before Jane, not John. The subject and object can be reversed as long as you keep the "to" before the right word. "John piace a Jane" Could be "A Jane piace John". They mean "John is pleasing to Jane" and "To Jane, John is pleasing", respectively.
Their example is wrong, isn't it? Because they say they're translating "John likes Jane" which should be "A John piace Jane" (or "Jane piace a John) right? To John Jane is pleasing? They switched John and Jane in the example, and then they talked about reversing order and made it super confusing.