根据短文内容，用方框内所给的单词的适当形式填入短文空格内，使短文意思正确、通顺，每词限用一次（每空一词）。并将所选单词填写在对话后面的横线上。

how,  safe,  thank,  play ,  be,  invent ,  no,  so ,  interest,  ask

Thomas Edison was a great American .________. When he was a child, he was always .________  questions and trying out new ideas. No matter .________hard it was, he never gave up.Young Tom was in school for only three months. His teacher didn’t understand why he had .________many strange questions. Most of them were not about his lessons. The teacher didn’t want to teach Tom any .________. He asked Tom’s mother to take the boy home. Tom’s mother taught him to read and write, and she found him to .________ a very good pupil. He learnt very fast and became very .________ in science.
One day , he saw a little boy .________ on the railway tracks at a station. A train was coming near quickly, and the boy was too frightened to move. Edison rushed out and carried the boy to .________. The boy’s father was so .________  that  he taught Edison to send messages by telegraph.