奥巴马宣布美国作为唯一一个曾经使用过原子武器的国家，有责任削减核武器，以使人类在21世纪免遭核武器伤害。

Obama declared that the US, as the only country ever to have used atomic weapons, had a special moral responsibility on nuclear disarmament to make life in the 21st century "free from fear".

youdao

随着制造核武器的物理知识的日益普及，以及制造核武器的精密技术愈来愈容易获得，许多国家—目前约有40个国家—从理论上说有能力制造核武器。

As the physics of nuclear weapons is more widely understood, and as precision technology is more easily obtained, many countries-perhaps 40 now-could in theory develop nuclear weapons.

youdao

随着制造核武器的物理知识的日益普及，以及制造核武器的精密技术愈来愈容易获得，许多国家—目前约有40个国家—从理论上说有能力制造核武器。

As the physics of nuclear weapons is more widely understood, and as precision technology is more easily obtained, many countries-perhaps 40 now-could in theory develop nuclear weapons.

youdao