Seven cows went for a walk around the pasture. The black cows with horns, the white cows with horns, and the black cows with spots went. The black cows without horns and the white cows without spots also went. Name the cow that didn’t go.
Just as cows look bemused and detached as they chew their cuds, so Luisa had an air of ______ as she chewed gum for hours in class.
现金牛产品(Cash cows)