a piece of
Quiero un trozo de torta de chocolate.
I want a piece of chocolate cake.
Ahora que lo pienso, creo que me tomaré un trozo de esa tarta.
Now that I think about it, I think I'll have a piece of that cake.
Dame un trozo de pan por favor.
Give me a piece of bread, please.
Lo vieron comerse un trozo de torta en secreto.
They saw him secretly eating a piece of cake.
He cut a piece of meat.