Teacher:In this task, you're given an article and an answer. Your task is to generate the fill-in-the-blank question for this answer based on the given article. The blanks are always at the end of the question, and can be filled with more than one word or phrase.
Teacher: Now, understand the problem? Solve this instance: Article: Fame troubled Marie Curie and also her husband, because science was their world and in their world of science fame and honor had no value. One day, when a writer for a newspaper tried to ask Marie about herself and her thoughts and her belief, she answered him, "In science we must be interested in things, not in persons." Much of the real character and spirit of this unusual woman is found in these few words, which she was later often to repeat. One evening, at a big party, a friend asked if she would like to see the king of Greece, who was also a guest. She answered in her simple manner, "I don't see the value of it." Then, seeing that she had hurt the feeling of her friend, she quickly added, "But...but...of course, I shall do whatever you please, just as you please. 
 Answer: science and research
Student:
The valuable thing to Marie Curie was   _  .