For weeks,President Obama has maintained that his record-breaking $3.6-trillion budget for the next fiscal year makes vital investments in energy,health care,and education that will pay dividends once the nation emerges from a deep economic recession.

VOA: standard.2009.03.22

If you get some of these in the upper atmosphere, a photon, an ultraviolet photon, has the energy capable of breaking this bond.

如果你把它放到大气层上，一个光子，一个紫外光光子，有能量可以破坏它的化学键。

麻省理工公开课 - 固态化学导论课程节选

If you get some of these in the upper atmosphere, a photon, an ultraviolet photon, has the energy capable of breaking this bond.

如果你把它放到大气层上，一个光子，一个紫外光光子，有能量可以破坏它的化学键。

麻省理工公开课 - 固态化学导论课程节选