题目内容：

    If you live in Shanghai, you might have to take a "lesson" in sorting garbage（垃圾分类）, as the city recently introduced new garbage-sorting regulations（条例）. It's now required that people should sort garbage into four categories, namely recyclable, harmful, dry and wet waste. However, if people fail to sort their garbage properly, they can be fined up to 200 yuan.

More cities are introducing similar regulations, following the practice in Shanghai. By the end of 2020, garbage-sorting systems will have been built in 46 major Chinese cities, including Beijing and Shenzhen, reported People's Daily.

According to a study by the Policy Research Center for Environment and Economy, under the Ministry of Ecology and Environment, over 90 percent of the public believe that garbage sorting is important for the protection of the environment. However, garbage sorting is still a big problem in China. Only 30 percent of participants said they think they are adequately（充分地）sorting their trash, the study noted.

According to Xinhua News Agency, it's partly because many people lack the willingness to sort their own waste. In the past, some previous garbage regulations didn't give clear fines for people who failed to sort garbage.

"It's a must to have a legal guarantee to promote garbage sorting." Liu Jianguo, a professor from Tsinghua University, told China Daily.

Liu Xinyu, a researcher of the Shanghai Academy of Social Sciences, told China Daily that the importance of the new regulations in Shanghai is to change the past voluntary action into compulsory action for everyone.

Aside from China, many other foreign countries have also introduced garbage-sorting regulations. In Japan, waste sorting has become a basic survival skill. In Germany too, people are asked to sort waste into specific categories. For example, in Berlin, people have yellow bins（垃圾桶）for plastic and metals and blue bins for paper and cardboard.

1.What do we know about garbage sorting in Shanghai?

A.It sets an example for many other cities in China.

B.People should put their garbage into two categories.

C.People will be fined 200 yuan each time they break the regulations.

D.Shanghai is the only city to introduce garbage-sorting regulations in China.

2.What is the current situation of garbage sorting in China?

A.Some people can properly sort their garbage.

B.Few people know the importance of garbage sorting.

C.People are not happy with the current garbage sorting regulations.

D.China's garbage-sorting problem is the most serious in the world.

3.Which of the following best explains "compulsory" underlined in paragraph 6?

A.Willing. B.Motivated.

C.Selected. D.Forced.

4.What is the main idea of the text?

A.Why garbage sorting is important.

B.How other countries sort garbage.

C.Garbage sorting has started in China.

D.The world's garbage problem is becoming worse.