题目内容：

    A city in South Korea, which has the world’s highest smartphone usage rate, has placed flashing lights at a road crossing to warn “smartphone zombies” (低头族) to look up and drivers to slow down, in the hope of preventing accidents.

The designers of the system were motivated by growing worry that more pedestrians (行人) addicted to their phones will become victims in a country that already has some of the highest injury rates among developed countries.

State-run Korea Institute of Civil Engining and Building Technology believed its system of flashing lights at crossings can warn both pedestrians and drivers.

In addition to red, yellow and blue LED lights on the road, “smartphone zombies” will be warned by flashing lights and a warning sent to the phones by an app that they are about to step into traffic.

“Increasing numbers of accidents are happening at pedestrian crossings, so these lights are needed to prevent these pedestrian accidents,” said KICT senior researcher Kim Jong-hoon.

South Korea has the world’s highest smartphone usage rate, according to Pew Research Center, with about 94 percent of adults owning smartphones in 2017, compared with 77 percent in the United States and 59 percent in Japan.

For now, the warning system is set up only in Ilsan, a city about 30 km northwest of the capital, Seoul, but is expected to go nationwide, according to the institute.

Kim Dan-hee, a 23-year-old citizen of Ilsan, welcomed the system, saying she was often too absorbed in her phone to remember to look at traffic. “This flashing light makes me feel safe as it makes me look around again, and I hope that we can have more of these in town,” she said.

1.What is the purpose of South Korea’s new warning system?

A.To prevent pedestrian accidents. B.To limit the use of phones.

C.To remind pedestrians to look around. D.To ensure drivers’ safety.

2.How does the writer introduce the high smartphone usage rate of South Korea?

A.By describing a scene. B.By making comparison.

C.By explaining a subject. D.By raising a question.

3.What’s Kim Dan-hee’s attitude to the new warning system?

A.Supportive. B.Indifferent. C.Objective. D.Doubtful.

4.What is the best title for the text?

A.Flashing lights at the crossing in different countries.

B.Watching out for safety while crossing the road.

C.South Korea ranking the world’s highest phone usage rate.

D.New warning system to prevent accidents in South Korea.