0:14 the secretary of the Navy now says the China is the most significant long-term challenge for the US military (2 words). 海軍長官は中国の軍事強化が米海軍にとって間違いなく長い目で見て大きな試練になるだろうと語った。
The Navy is extending the range of its fighter jets by using unmanned aircraft for refueling
