Place Commas Where They Belong -- Answers

Ever since the first astronomer looked through a telescope[,] astronomers have relied on these devices to help them understand the heavens. Early telescopes were useful only to receive visible light[,] but in the past thirty years scientists have developed more sophisticated telescopes[,] some of which can receive radio waves[,] gamma rays[,] and ultraviolet light. At the present time[,] scientists are working on a telescope that can receive infrared light[,] a development that will prove invaluable to space exploration. The infrared telescope will allow astronomers to see configurations invisible to ordinary telescopes. The telescope will be able to explore[,] among other phenomena[,] the development of planets from clouds of gas and dust. The telescopes will also be able to help astronomers to better understand black holes. The cost of an earth-mounted telescope is estimated to be $80[,]000[,]000; the cost of an airborne telescope[,] $230[,]000[,]000. According to John Bahcall[,] Ph.D.[,] of the Institute for Advanced Studies in Princeton[,] New Jersey[,] the cost will be well worth it. The study of infrared light will allow astronomers[,] physicists[,] and other scientists to tell us a great deal about how our universe was formed[,] and it will help them determine what will happen to our universe in the future. As one researcher explained[,] "The more we know about what's out there[,] the better we understand what's down here." The infrared telescope sounds like an exciting development[,] don't you think?

With the increasing number of choices that we have today[,] choosing a major field of study is harder than ever. In fact[,] most students change their majors more than once before they graduate. New demand for technologically competent employees in such fields as computer networking[,] biotechnology[,] and desktop publishing has opened new possibilities that never before existed. The technology sector is a promising field[,] generally speaking[,] but few students even check on their job prospects before they choose a major. If you want to know about the pay ranges and job opportunities for a certain major[,] try asking for information at your counseling center[,] employment center[,] or library. As the old saying goes[,] "Look before you leap."