根据以下材料，回答{TSE}题
What enables some people to get big creative breakthroughs while others only get small and non-creative breakdowns,blaming themselves and society?Are some people“gifted”?Are there other factors 21 work—factors that we have more control over than we think?
While nobody can deny the 22 that some people seem to be blessed with particular creativity,research shows that anyone can 23 their chances of coming up with new and original ideas 24 they would only engage themselves more in the process of 25 ．It´s the old Thomas Edison thing about“discovery 26 99 percent perspiration(汗水)and 1 percent inspiration．” 27 ,the studies prove this:great creative breakthroughs usually happen only 28 intense periods of struggle．It is sustained effort towards a specific goal 29 ually prepares for great creative insights．
This kind of sustained effort does not always 30 immediate results,a fact that not only separates the innovators(革新者)from non-innovators,but 31 leads some people to conclude that it is just not 32 for them．“Maybe I should have gone to medical school like my mother wanted,”they wonder when the breakthrough is 33 to be found．Alas,one forgets during their inevitable encounters 34 self-doubt,that the big surprise is never 35 ．Indeed,it can happen at any time and place．
{TS}第21题的答案是(　　)