Ride-sharing services are thought to help to reduce pollution since fewer people use private vehicle

Ride-sharing services are thought to help to reduce pollution since fewer people use private vehicles and cause carbon dioxide．However, a new study has found that these services result in much more pollution than other kinds of private and public transportation．Ride-sharing trips also draw passengers away from more environmentally-friendly methods of travel, like public transportation, walking or biking, the study found．
Several studies in recent years have suggested that ride-sharing services like Uber and Lyft can worsen traffic problems in cities, which continue to have high rates of private vehicle ownership．
The new study, carried out by the nonprofit group Union of Concerned Scientists, represents an attempt to center on how ride-sharing services affect pollution．The research examined the effects of ride-sharing services on seven of America's largest cities．Overall, the researchers reported that ride-sharing trips now “result in about 69 percent more climate pollution on average than the trips they replace”．The study notes that the same passengers could have chosen to travel by bus, train, bike, scooter(小型摩托车)or on foot．
One of the big reasons they give for this result is that ride-sharing vehicles are often driven with no passengers in the car．This happens when drivers are either waiting for rider requests, are on the way to pick up passengers or are driving between pickups．
This situation, known as“deadheading” takes up about 42 percent of the ride-sharing driving activity, the study found．The researchers said that “deadheading” results in about 50 percent more carbon dioxide than one person driving in a private vehicle．
The study urges services like Uber and Lyft to increase the number of electric vehicles on the road and to improve connections to public transportation centers．The two companies already operate businesses that offer electric scooters and bikes and have begun to include public transportation information in their systems．In some cities, they have also promoted vehicle electrification．
8．According to the text, it is generally thought that car-sharing services _____________．
A．lower the price of private cars B．guarantee a healthier lifestyle
C．greatly cut down travel expenses D．are environmentally-friendly
9．What is the biggest cause of more ride-sharing pollution?
A．The so-called “deadheading”． B．The old way vehicles travel．
C．The huge number of passengers． D．The unfamiliar ride-sharing trips．
10．What can we say about the study?
A．It is opposed by ride-sharing services． B．It is actually of practical significance．