请给出一个英文的科技故事，故事要有开头、过程和结尾，一共50个单词，不要有任何标点。

Mary always dreamed of becoming an engineer
One day she invented a smart robot
People admired her creativity
Mary s invention changed the world
user
Mary always dreamed of becoming an engineer
One day she invented a smart robot
People admired her creativity
Mary's invention changed the world
assistant