A、They encourage homelessness. B、They are a safety hazard. C、They take up parking spaces. D、They can be stolen. C概括录音开头两句即可得出答案是

(21)One of the complaints of city residents, not surprisingly, is the lack of parking. This problem is partly caused by all the abandoned cars on the streets. It has been estimated by A to Z Towing Inc., a nationwide tow-truck agency, that (19)over one million cars are abandoned on the streets and alleyways of the nation’s cities. Each year, approximately a third of those cars are removed and destroyed. The rest of the cars, which are not removed, take up parking spaces and make neighborhoods look rundown.
    A survey of twenty cities by A to Z reports that as much as 30 million dollars is spent annually to tow away and dismantle abandoned vehicles. One city alone, Los Angeles, spends five million dollars a year to control the accumulation of abandoned cars on its streets. Even though the city spends so much money on the program, it is always fighting a losing battle as more and more cars are constantly coming off the production line.
    Boston, on the other hand, which spends most of its money on museums and libraries, does not appropriate tax money to clear abandoned cars off the streets. In Boston the problem has been dealt with by (20)a non-profit government agency called Street Horizons, which uses the money from the recycling of metal in the cars to pay for the cost of towing them. The program in Boston sounds good although it has not completely reached financial independence from the federal government yet. Until a truly self-sufficient program for removing old cars is developed, it will remain a serious problem.
19. How many cars are towed from the streets each year?
20. What is Street Horizons?
21. What is the problem with abandoned cars?