Take one example from petrochemical products. CPC has had a monopoly on "naphtha cracking." Its main product--ethylene--is an indispensable raw material for all petrochemicals goods.
以油品來說，「輕油裂解」一向是中油的獨門生意，主要產品乙烯更是所有石化產品都不可或缺的原料。