"My friend and I touched an elephant."
Translation:Meu amigo e eu tocamos em um elefante.
Yes, that too!
Tocar violino = Play violin.
Tocar em um violino = Touch ("on") a violin.
Eu toco piano = I play piano
Eu toco (n)o piano = I touch ("on")the piano
The "em" tells us that it means "touch". I added the "on" in parentheses to show the difference, but I don't know if that helps. Think of it this way: usually, if we are talking about instruments, we just say tocar + instrument. If other words are stuck in between them (such as: the, on, a), it is likely that it means "touch". I just figured that out, so there may be flaws in that tip... but I think it actually works. =]