单选题 .  A person may have an idea about himself that will prevent him from doing good work. He may have the belief that he is not capable (有能力的) of it. A child may think he is     1    because he doesn't understand how to make the     2    of his mental faculties (才能). Older people may be mistaken that they are incapable of learning things new because of their     3    .
    A person     4    believes that he is incapable will not make a real effort because he feels that it would be useless. He won't go at a job with confidence necessary for     5    , and he won't work his hardest way, even though he may think he is doing so. He is     6    likely to fail, and the failure will     7    his belief in his incompetence.
    Alfred Alder, a famous doctor, had     8    like this. When he was a small boy, he had a poor     9    in maths. His teacher told his parents he had no ability in maths in order that they would not     10    too much of him. In this way, they two     11    the idea. He accepted     12    mistaken thinking of his ability, felt that it was useless to     13    and was very poor at maths,     14    as they expected.
    One day he worked at a problem     15    none of the other students had been able to solve.
    Alder     16    in solving the problem. This gave him confidence(信心). From then he     17    with interest, determination and purpose, and he soon became especially good at     18    . He not only proved that he could learn maths well, but luckily he learned     19    in his life from his own experience that if a person goes at a job with determination and purpose, he may     20    himself as well as others by his ability.1.