You have a slightly different enzyme than the A people, so you build a slightly different structure, and those of you that are AB have the enzyme from your mother, the other enzyme from your father, and now you make both of these structures in roughly equal proportions.
Dere har et litt annerledes  enzym enn A-folka, som lager en litt  annerledes struktur, og de av dere som har AB har enzymet fra mødrene deres,  det andre enzymet fra faren deres, og dere lager begge disse strukturene i omtrent like store mengder.