Millions of highly polluting used cars from rich countries are being" dumped" on developing nations，according to a UN report.Between 2015 and 2018，some 14 million older，poor quality vehicles were exported（出口） from Europe，Japan and the US.Four out of five were sold to poorer countries，with more than half going to Africa.
   Experts say that up to 80% failed to meet-minimum safety and environmental standards in exporting countries.As well as causing accidents，these cars make air pollution worse and contribute heavily to climate change.Many of the vehicles have also been tampered with（篡改） to remove valuable parts.
   The report，published by the UN Environment Programme （Unep），says that both exporters and importers need to put tougher regulations （rules） in place to stem the flow of these jye.ais.Car ownership is booming（繁榮） all over the world with an estimated 1.4 billion vehicles on the roads，a number that's expected to reach around two billion by 2040.Much of that growth is happening in developing countries in Asia，Africa and Latin America.
   A second study on the issue，by the Netherlands Human Environment and Transport Inspectorate，shows that many cars and vans shipped from Dutch ports to Africa are outdated and contribute to worsening air quality on the continent.According to the authors，
these cars are both "dangerous and dirty." They believe these imports are responsible for increased levels of road accidents in many poorer African and Asian countries.
   The growing realization of the dangers posed by these cars has seen several importing countries strengthen their regulations.Morocco only permits cars less than five years old to be imported.Kenya also has an age limit of eight years for imported cars.On a regional level，the Economic Community of West African States （ECOWAS），representing15 countries，has set cleaner fuel and vehicle standards from January 2021.
But to really deal with the issue will require action at both ends of the supply chain. "On one hand，I think it's unethical（不道德的） that these developed countries export vehicles that are not roadworthy on their own roads，" said Rob de Jong，one author." On the other hand，why have the importing countries been waiting so long to put in place some minimum standards？So I think the responsibility is not only on the exporting country，it's really a joint responsibility."

（1）What problems do the "dumped" cars cause to developing countries？

C

C

A．Car ownership is booming in these countries.
B．These countries are becoming poorer and poorer.
C．They worsen the air quality and lead to road accidents.
D．These countries have to make rules to handle climate change.
（2）The underlined word "stem" in paragraph 3 might mean

A

A

A．stop
B．increase
C．lead
D．distract
（3）To handle the problem，Rob de Jong suggests that

C

C

A．importing countries strengthen their regulations
B．exporting countries get punished for their behavior
C．both exporting and importing countries take action
D．limit be set on the age of the imported cars
（4）What's the main idea of this passage？

A

A

A．Many used cars are exported to poor countries，which calls for action.
B．Developing countries are very weak in dealing with the import of used cars.
C．It's selfish for developed countries to export vehicles that are not roadworthy on their own roads.
D．Used cars contribute heavily to air pollution and climate change in poor countries.