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从上个世纪40年代起,美国开始研制 X 系列战机。从 X-1到今天的X-43A 极速飞行器,空间作战兵器又有了新突破。
From the 40s of last century, the United States began to develop X-series fighters. From the X-1 to today’s X-43A speed craft, spacecraft have made new breakthroughs.