【中文版】

垄断是指一个或多个市场或行业中的一种或多种商品或服务的生产和销售完全或几乎完全由一个或几个公司控制的现象。这些公司被称为垄断者，他们通过控制市场份额和价格，获得高额利润并阻碍竞争。

垄断的形成原因有多种，包括技术、法律、经济和政治因素。例如，某些行业可能因为其特殊的性质或技术要求，只有少数公司能够生产或提供服务；或者政府可能通过授权或法规，将某些行业或市场的经营权授予特定的公司。

垄断可能导致消费者遭受损失，因为他们无法在市场上选择其他公司的产品或服务，而且价格可能被提高。此外，由于缺乏竞争，垄断者可能缺乏创新和改进的动力，这也会对消费者造成损失。

为了防止垄断的出现，政府通常会采取一些措施，如反垄断法和监管措施，来限制市场势力的滥用和保护消费者的利益。

【英文版】

Monopoly refers to a situation in which one or more companies control the production and sale of all or almost all goods or services in a market or industry, completely or almost completely. These companies are called monopolists and they obtain high profits by controlling market share and prices, and hinder competition.

There are various reasons for the formation of monopoly, including technological, legal, economic, and political factors. For example, some industries may have special characteristics or technical requirements that only a few companies can produce or provide services; or the government may grant certain industries or markets to specific companies through authorization or regulations.

Monopoly may cause consumers to suffer losses because they cannot choose products or services from other companies in the market, and prices may be raised. In addition, due to the lack of competition, monopolists may lack the incentive to innovate and improve, which will also harm consumers.

To prevent the emergence of monopoly, governments usually take some measures, such as anti-monopoly laws and regulatory measures, to limit the abuse of market power and protect consumers' interests.