86. Which of the following can be the best title for the passage?

1. A Decline in Car Emissions
2. White Roofs or Black Pavements
3. The Effect of Lightening-up Roofs
4. Climate Change and Extreme Weathers

87. As indicated by the passage, black roofs ____.

1. are better than snowy white ones
2. reflect no heat from the sun
3. are more expensive to build in the urban areas
4. are supposed to be replaced by snowy white ones

88. If they are converted to white or cooler colors, all roofs in the world in their lifetime ____.

1. can absorb 1.2 gigatons of CO₂ a year
2. could serve as 300 million cars in terms of emission
3. would offset the emissions from 300 million cars
4. would offset about 24 gigatons of CO₂ as emitted from the cars

89. According to the passage, it is hard and expensive to keep the urban buildings cool because of ____.

1. the heat-island effect
2. the lack of seasonal winds
3. the local unique weather
4. the fast urban shrinkage

90. Energy Secretary Steven Chu implies that ____.

1. nothing could be more effective in cooling global warming than method he has advocated
2. the method in question still needs to be justified in the future
3. our global carbon emissions can be reduced by half if cool roofs are installed
4. weather change and global warming can be addressed in no time

(Reference keys.)