19. Which of the following is not considered as an instanced of “incomplete learning”？
A） Poor hearing.
B） Bad eyesight.
C） Lack of attention.
D） The attempt to learn too many new things at the same time
答案： D
解析：最后一句的中间部分For example， the older person perhaps had trouble hearing， or poor vision， or inattention， or was trying to learn the new thing at too fast a pace没有提到Ｄ项的内容。Ｄ项仅仅说的是心理原因造成的结果。
20. What we call mental decay is usually a sign of ____.
A） a low – spirited state.
B） a worsening state of health.
C） old age.
D） nervous tension
答案： A
解析： 细节题。文章的最后两句都是说明这个问题a sign of a depressed emotional state是说明的mental因素。
