2. 职称英语
  3. In 1961, NASA has encouraged studies of space-planes that could be built using e

In 1961, NASA has encouraged studies of space-planes that could be built using e

游客2023-09-17  79
问题 In 1961, NASA has encouraged studies of space-planes that could be built using existing technology. [br] The X-34 has a reusable lower stage and an expendable upper, the goal of designs is______.
选项
答案 to reduce the cost
解析 文章第6段第1句，X-34运载火箭有上下两级火箭组成，这样设计的目的是减少发射小型卫星的成本。
转载请注明原文地址:http://tihaiku.com/zcyy/3021694.html
相关试题推荐
随机试题
最新回复(0)