完形填空。阅读下列短文，从所给的四个选项中选出最佳答案。 A young man once asked Albert Einstein, the great scientist, 1 the secret of success(成功) is. The scientist told him that the secret of success is 2 work. A few days later the young man asked him the same question again. Einstein was very 3 . He did not say 4 , but wrote 5 words on a piece of paper and handed it 6 the young man. The young man looked at the piece of paper. 7 it was written: A=X+Y+Z. 'What does this 8 ?' asked the young man. 'A means success,' 9 the old scientist. 'X stands for(代表) hard work, Y stands for good methods(方法) , and Z…,Z means stopping 10 and getting down to work.' (     )1. A. how (     )2. A. hard (     )3. A. pleased (     )4. A. anything (     )5. A. a little (     )6. A. for (     )7. A. Over (     )8. A. mean (     )9. A. say (     )10.A. talk B. what B. easy B. happy B. nothing B. little B. to B. On B. tell B. explained B. to talk C. which C. good C. angry C. something C. a few C. of C. In C. show C. told C. talked D. why D. bad D. sorry D. everything D. few D. with D. At D. give D. spoke D. talking