The American space agency, NASA, has launched two unmanned probes to the moon, the first step of a plan to send humans back to the moon and beyond.是什么意思_The American space agency, NASA, has launched two unmanned probes to the moon, the first step of a plan to send humans back to the moon and beyond.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句