【原创】The hardest thing is to ______ less when you can ______more.

【原创】 Green roofs have an ______effect, helping reduce the amount of energy______ to heat a building in winter and cool it in summer.

【原创】 Vehicles, coal-burning, airborne dust and industrial production ______85 to 90 percent of the major airborne pollution sources in most Chinese cities, the newest research shows.

【原创】 In 1884 the term“Junk”came to mean“old refuse from boats and ships”，and______ it came to mean“trash”in Western culture .

【原创】 Shanghai is going to introduce sky train into the city, with ______transparent carriages meant to provide passengers with______ unobstructed 360-degree view of the city, the Shanghai Morning Post reported on Thursday.