[填空题]Among the alternative energy sources,______, and coal are the cheapest forms today.

[填空题]Among the alternative energy sources,______, and coal are the cheapest forms today.

[填空题]Developing alternative energy sources is the most effective method to cope with energy problems both in the short and long terms.

[填空题]Harrison:
Of all energy sources, nuclear energy has perhaps the lowest impact on the environment, especially in relation to kilowatts produced, because nuclear plants do not emit harmful gases, require a relatively small area, and effectively mitigate other impacts. In other words, nuclear energy is the most" eco-efficient" of all energy sources because it produces the most electricity in relation to its minimal environmental impact. There are no significant adverse effects to water, land, habitats, species and air resources
Jeffery:
The radioactive particles in low-level waste emit the same types of radiation that everyone receives from nature. The U. S. Nuclear Regulatory Commission requires that releases of radiation at a disposal site not exceed an annual dose to any member of the public of 25 milligrams to the whole body. In comparison, the average American is exposed to about 360 milligrams of radiation annually mostly from natural sources ( such

[判断题]
The funds to expand alternative energy research are 2,700 million dollars, a 53 percent increase over the 2006 funding level.

[单项选择]Compared to alternative energy, one of the disadvantages of fossil fuels is ______.
A. mining is difficult
B. it costs a lot of money to preserve
C. they are difficult to be processed
D. they are non-renewable