Hi, everybody. One of the things that makes America so strong is our spirit of innovation. Our drive to invent and harness new technologies to tackle our greatest challenges. It's how we won the r
THE PRESIDENT: Earlier this week, I signed into law the American Recovery and Reinvestment Act -- the most sweeping economic recovery plan in history. Because of this plan, 3.5 million Americans will
Well, let's go back to this picture. There's one challenge symbolized at the top, but there's another challenge to science symbolized at the bottom. 好吧，让我们回到这张图片。在其上部有一个符号化了的科学挑战。而在其下部同样有一个符号化了的科学挑战。
