[简答题]The heat that is produced by burning garbage is used to boil water. (Passage 2)

[简答题]The heat that is produced, by burning garbage is used to boil water. (Passage 2)

[简答题]Another problem is that burning garbage can pollute the air.

[简答题]Burning garbage might be one kind of energy source that we can use to help meet our energy needs. (Passage 2)

[简答题]Burning garbage is not a new idea. Some cities in Europe and the United States have been burning garbage for years. (Passage 3)

[简答题] A survey of 25 cities, produced for the US Conference of Mayors in 2003, reported that families make up 40% of the homeless population. Nationally, the situation is even worse. In 2000, the Urban Institute found that children under the age of 18 make up 39% of homeless people. Tragically, some estimates indicate that youth are the fastest-growing segment of those without homes. These kids and teens face incredible obstacles in all aspects of their lives, including their education. As the National Coalition for the Homeless notes, "School is one of the few stable, secure places in the lives of homeless children and youth — a place where they can acquire the skills needed to help them escape poverty." But despite many successful efforts to improve their access to schooling, homeless youth continue to face financial, bureaucratic, and practical barriers to getting a quality education. On December 21st, the first day of winter, communities around the nation will observe National H