Final answer:
The proper query to search for the words allow, allowed, and allows is to use the OR operator.
Step-by-step explanation:
The proper litigation-support-system query to search for the words allow, allowed, and allows would be:
allow OR allowed OR allows
By using the operator OR between the words, you are instructing the system to search for any of these words in the document or database. This helps ensure that you retrieve all relevant results that include any form of the word, such as singular, plural, past tense, etc.
For example, if you were searching for documents related to permissions, using this query would return results that include the words 'allow,' 'allowed,' and 'allows.'