单选题：Questions are based on the following passage. Researchers h

Questions are based on the following passage.
Researchers have found that people’S mental abilities peak at 22 before beginning to deteriorate(恶化)just five years later. Professor Timothy Salthouse said the results suggesmd that therapies 36 to prevent or reverse agerelated conditions may need to start earlier，long before people become pensioners. Almost half of over 50s are“unaware of leading cause of blindness”. “Results converge on a 37 that some aspects of agerelated cognitive 38 begin in healthy，educated adults when they are in their 20s and 30s，”he said.
The study of 2，000 men and women 39 over seven years. The 40 , aged between 18～60，were asked to solve visual puzzles，recall words and story details and spot patterns in letters and symbols. Similar tests are often used to 41 mental disabilities and declines，including dementia(痴呆).
The research by the University of Virginia found that in nine out of 12 tests the average age at which the top performance was 42 was 22. The first age at which performance was 43 lower than the 44 scores which was 27 for three tests of reasoning，speed of thought and spatial visualization. Mereory was shown to decline from the average age of 37. In the other tests，poorer results were shown by the age of 42.
However，the report published in the academic journal Neurobiology of aging，found that abilities based on 45 knowledge，such as performance on tests of vocabulary or general information，increased until at the age of 60.
A．available
B．diagnose
C．achieved
D．significantly
E．accumulated
F．decline
G．respondents
H．lasted
l．recipients
J．conclusion
K．particularly
L． increase
M．designed
N．treat
O．peak
第(36)题应填__________