translation.en: If that Martian looked at battlefields, they would find that people had only muskets at the time of the Civil War and that they had repeating rifles at the time of the Spanish-American War, and then they had machine guns by the time of World War I.
translation.zh: 而如果那火星人去看看战场， 他们会找到在内战期间 只带着步枪的战士； 在美西战争期间 用连发猎枪的战士； 还有在一次世界大战期间 用机关枪的战士。