You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
You are given an English sentence with a blank, and you need to predict the missing word. After completing, the whole sentence should be gramatically correct and non-ambiguous.

The kid on the street is ____ soccer
Solution: playing
Why? This is the original sentence 'The kid on the street is playing soccer' So, we have correctly predicted the missing word to be 'soccer'

New input: and that if she noticed anything odd or out of place she would never rest until she had ferreted out the whys and wherefores thereof there are plenty ____ people in avonlea and out of it who can attend closely to their neighbor's business by dint of neglecting their own
Solution:
of