阅读：伟大发明家的故事 — 英语词汇题
题目
阅读短文，根据故事内容补全单词。
Thomas Edison wanted to make a lamp that could stay bright for a long time. He tried many materials for its thin wire. One test lasted much longer than the others, and his work helped make electric light more useful. People called Edison an i______ because he created new things.