一般加-es Negro-Negroes, hero-heroes, potato-potatoes, tomato-tomatoes 不少外来词加-s piano-pianos, photo-photos, auto-autos, kilo-kilos, solo-solos 两者皆可 zero-zeros/zeroes, volcano-volcanoes/ volcanos 7 以元音字母加-o结尾的名词加-s ...