人类一刻也没有忘记飞天的梦想。当军用火箭作为战争的重要武器问世后,把人送入外层空间的试验就开始了。进行这些试验,人类自然就想起了动物,由于狗、猿的血液循环系统和呼吸系统与人很相似,在长期试 Humans have never forgotten the dream of flying. After the military rockets were introduced as an important weapon of war, the test of sending people into outer space began. In these experiments, humans naturally think of animals. Because the blood circulation system and respiratory system of dogs and crickets are similar to humans, they are tested for a long time.