单词:MAC (maximum air concentration)
单词:MAC (maximum air concentration) 相关文章
STEVE EMBER: Im Steve Ember. SHIRLEY GRIFFITH: And Im Shirley Griffith with EXPLORATIONS in VOA Special English. Today we travel to India by way of the John F. Kennedy Center for the Performing Arts in Washington, D.C. This cultural organization is c
Psychologically defined, concentration is the process of centering one's attention over a period of time. In practical application, however, concentration is not as simple to deal successfully with as the definition may imply. For this reason, it is
By Melinda Smith Washington 10 July 2007 A recent study in the Journal of the American Medical Association shows that older people who carry certain genes are more susceptible to a loss of their central vision. That loss of sight is an advanced form
Siri Comes to Mac Computers Earlier this month, Apple announced new technology at its yearly Worldwide Developers Conference (WWDC). In the last Personal Technology report, we talked about the changes to Apples iPhone and iPad operating system. Today
HEALTH REPORT - Progression of Age-Related Macular Degeneration By Nancy Steinbach Broadcast: Wednesday, January 28, 2004 This is Phoebe Zimmermann with the VOA Special English Health Report. American
今天我们要讲的习惯用语都有air这个词。大家都知道air是空气。早在十七世纪,意大利科学家伽利略发现空气似乎没有实质却有重量。后来人们进一步发现高山顶上的空气要比海平面上的空气