At the dawn of the 21st century, the United States of America faces a broad and complex array of challenges to our national security.
21世纪伊始,在国家安全方面,美国面临着一系列的广泛而又复杂的挑战。
At the dawn of the twentieth century, the United States emerged as a world power, and the U.S. press proved its influence.
在20世纪的黎明,美国崛起为世界强权,它的媒体也证明了它的影响力。
At the dawn of the 20th century, technology was booming and it seemed that anything was possible for the future.
在二十世纪之初,科技繁荣发展,似乎在未来什么都有可能。
At the dawn of agriculture, there were around 5 million people on the planet.
在农业时代的开端,地球是大概有五百万人。