A、The number of passengers dropped sharply. B、It served more and more commuters. C、The number of stations increased to 50. D、It

The Glasgow Subway first opened in 1896 as a cable-hauled system. It is generally recognised as the world’s third underground railway, after London and Budapest. In its long history, it has never been expanded, remaining as a single loop line with a mere 15 stations. At its peak, it served the shipyard workers on the south side of the city. In the 1960s, there was a decline in the ship building industry, and the popularity of private transport grew. As a result, the subway saw a rapid decline in ridership. It ran with little further change until 1977 when its new operators closed it for major modernisation investment. Carriages were replaced, ventilation was improved, and the main depot was also renovated and fitted with connecting tracks to replace the outdated crane transfer mechanism. The subway, in its present form, reopened for operation in April 1980. Since its relaunch, the subway has seen a revival in its fortunes. It serves as a viable alternative to other forms of transport, and has gone a long way to alleviate traffic jams in the city centre. In 1996, the system reached an important milestone, 100 years. To commemorate this special event, the colour scheme of the train carriages was updated. Recently, high-tech systems such as smartcard ticketing machines and smart gates are used across all subway stations. The smart card provides more convenient travel, and passengers simply top up their cards and tap them to get in and out the subway. Since its launch, the technology has been adopted by more than 100,000 subway customers.
    12.What baffling phenomenon is discussed in the passage?
    13.Why was the Glasgow subway closed in 1977?
    14.Why does the Glasgow Subway remain important today?
    15.What does the passage say about all subway stations in Glasgow nowadays?