阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中词语的正确形式填空，并将答案填写在答题卡标号为16—25的相应位置上。
Stephen Hawking, who is the most famous physicist, was born in Britain on January 8th, 1942. As a child, he was enthusiastic about 16 (design) complicated toys but 17 (fortune), in his twenties, he suffered 18 a disease that was impossible to be cured, 19 was a great challenge for him. However, not only was he positive about the misfortunes 20 eventually he defeated all the obstacles but also he was 21 (absorb) in his research in the universe. In 1988, his best-seller A Brief History of Time was published, 22 which he put forward the idea 23 time itself has a beginning, and that it will have 24 end. In conclusion, he has made outstanding 25 (contribute) to the fields of cosmology and quantum gravity.
