Too many cars have created a lot of serious problems in our world. Besides congestion , accidents and fast fuel consumption , cars are responsible for a good part of air pollution in big cities. All the time, they are pumping huge amounts of waste gases into the atmosphere. These gases are very harmful, causing disease and even death. Last winter, car fumes  formed heavy smog over Beijing, making the sky gloomy for weeks and deteriorating people's health. One possible solution is to design and develop clean cars and clean fuels. In Tsinghua University, campus buses are driven by electricity. In Beijing some of the public buses begin to run on natural gas, which does not give off as much carbon dioxide as the petrol. But it may take decades for the new models of clean cars to completely replace the traditional ones. Another solution is to develop modern public transportation systems and restrict  the use of private cars. If the price of petrol rises constantly and the public vehicles  are efficient and convenient enough, most people will not use private cars. And the total number of cars in big cities will reduce greatly. On the whole, the elimination  of air pollution needs the co-efforts from the government, the public and the environments. This problem will be solved only with the help of science and technology. Which of the following is TRUE according to the passage?
New models of clean cars will soon replace the traditional cars Public transportation should replace all the private cars In some university, electricity is used in school buses It is only the government's efforts that can help solve air pollution caused by cars