But the creation of a layered defense, which attempts to intercept the missile at multiple stages of its trajectory, is not necessarily a cost-effective strategy.是什么意思_But the creation of a layered defense, which attempts to intercept the missile at multiple stages of its trajectory, is not necessarily a cost-effective strategy.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句