听短文，根据短文填空。短文念两遍。 One day, a young man asked Albert Einstein, a great German scientist, 1 the secret(秘密) of success (成功) was. The scientist told him that the secret of success is hard work. A few days 2 the young man asked him the same question again .Einstein was very 3 . He did not say anything, but wrote a few 4 on a piece of paper and handed it to the young man. The young man looked 5 the piece of paper. On it was 6 : A=X+Y+Z.' What 7 this mean?' asked the young man.'A means success,' 8 the old scientist. 'X means hard work, Y means good methods(方法)，and Z…Z mean 9 talking and start to 10 ' (     ) 1. A. who (     ) 2 .A. ago (     ) 3. A. worried (     ) 4. A. words (     ) 5. A. on (     ) 6. A. answered (     ) 7. A will (     ) 8. A. said (     ) 9. A. go on (     ) 10. A. do B. whether B. before B. happy B. word B. up B. written B. shall B. thought B. stop B. read C. what C. earlier C. angry C. sentences C. down C. read C. does C. believed C. enjoy C. write D. which D. later D. disappointed D. sentence D. at D. found D. did D. told D. try D. work