Operating assets are assets that can provide goods or services to the society in production and circulation. The unit of use of operating assets is an enterprise with the status of a legal person, and its operation should be based on the principle of pursuing economic benefits. From an accounting perspective, it mainly refers to enterprises Assets that are held for-profit purposes and are actually profitable. According to the above definitions, Which of the following are not classified as "operating assets":. ['Backlog of black and white TVs in a TV factory.', 'Hydropower station that has not been put into use during construction.', 'Bank deposits used by a foreign trade company to pay taxes.', 'New laboratory equipment and equipment purchased by a key middle school.']