Task: Sentence Expansion
Input (English): A monopoly usually happens when there is no economic competition to produce the product or service and there is no available substitutes to the product or service .
Output (English): Monopolies are thus characterized by a lack of economic competition to produce the good or service , a lack of viable substitute goods , and the possibility of a high monopoly price well above the seller 's marginal cost that leads to a high monopoly profit .