According to scientists, our mental abilities begin to from the age of 27 after reaching the highest level at 22.
A. differ
B. shrink
C. fail
D. decline
网友回答
A. differ
B. shrink
C. fail
D. decline
解析：根据句意：根据科学家研究，我们的精神气在22岁达到高峰值之后便从27岁开始下滑（decline）。Differ不同；shrink缩水；fail失败、衰竭，均不符合语境，故排除。