奥巴马每周电视讲话:总统谈论美国的创新精神
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 race to invent the lightbulb and the Internet; it's why we were first to the Moon and Mars. It's why I keep models of American inventions like the telegraph in the Oval O...