题目内容：

    UW’s Jason Shogren and Linda Thunstrom, along with Jonas Nordstrom of the Lund University School of Economics and Management, have documented that two-adult households with children emit over 25 percent more carbon dioxide than two-adult households without children.

The study involved an analysis of expenditures on goods and services by households in Sweden. The researchers found that parents with children at home consume goods and services that emit CO2 in the areas of food, such as meat, and transportation, such as gasoline, at higher rates than childless households.

The economists note that time constraints (约束) become more demanding, and convenience may become more important, when people have children.

“Parents may need to be in more places in one day,” resulting in people driving themselves instead of using public transportation or bicycling, the researchers wrote. “They also need to feed more people. Eating more pre-prepared, red meat carbon-intensive meals may add convenience and save time.”

The distinction in the carbon footprints of Swedish households with and without children is particularly striking, as concerns about climate change are more pronounced in Sweden than most other developed counties. Most Swedes believe climate change is real and have accepted sizable CO2 taxes, and households with children are given financial aid, which helps to alleviate some of the time shortage for parents to a certain extent.

“If we’re finding these results in Sweden, it’s pretty safe to assume that the distinction in carbon footprints between parents and nonparents is even bigger in most other Western countries,” Thunstrom says.

“Becoming a parent can transform a person, he or she thinks more about the future and worries about future risks imposed on their children and of spring,” Shogren says. “But, while having children might be transformational, our results suggest that parents’ concerns about climate change do not cause them to be ‘greener’ than non-parent adults.”

1.According to the study, compared with the households without children, the households with children __________.

A.emit more carbon dioxide

B.consume more goods and services

C.attach more importance to the quality of goods and services

D.are less concerned about carbon footprints

2.Why do two-adult households with children have higher carbon footprints?

A.They prefer to eat red meat prepared in advance.

B.They aren’t concerned about climate change.

C.They drive cars more as a consequence of time pressure.

D.They need to purchase more goods and services.

3.The underlined word “alleviate” in paragraph 5 refers to __________.

A.solve B.heighten C.worsen D.ease

4.What is the main idea of the passage?

A.Being a parent will cause a person to be more concerned about carbon emission.

B.Carbon footprints grow with parenthood because of increased time constraints and the need for convenience.

C.The increasing expenditures on goods and services by households help raise the awareness of carbon footprints.

D.The difference in carbon footprints between parents and nonparents is much severer in other western countries than in Sweden.