原來你連英文都唔識,中英文都唔識真係笑死人。
原文係5倍音速以上囉,這個定義係-高超音速。
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F-17 Dongfeng medium-range ballistic missiles equipped with a DF-ZF hypersonic glide vehicle, involved in an October 2019 military parade to mark the 70th anniversary of the Chinese People's Republic. The DF-27 is a new and improved version of the DF-17
Hypersonic missiles travel at more than five times the speed of sound in the upper atmosphere