As a NOUN:
* The rule of singular and plural: "Exhaust" is a singular noun. If you have multiple instances of exhaust, you'd use "exhausts."
* The rule of capitalization: "Exhaust" is usually lowercase unless it's the first word in a sentence or part of a proper noun (e.g., "The Exhaust System").
As a VERB:
* The rule of verb conjugation: "Exhaust" can be conjugated depending on the tense and subject. Examples:
* Present tense: I exhaust, you exhaust, he/she/it exhausts, we exhaust, you exhaust, they exhaust
* Past tense: I exhausted, you exhausted, he/she/it exhausted, we exhausted, you exhausted, they exhausted
* Past participle: exhausted
* Present participle: exhausting
Other Considerations:
* The rule of grammar: "Exhaust" can be used in various grammatical constructions, including:
* Subject of a sentence: The exhaust fumes were noxious.
* Object of a verb: The engine exhausts gases.
* Adjective: I am exhausted from work.
Without more information about the specific sentence or context where "exhaust" is used, it's impossible to say which rule applies most closely.
Please provide more information, and I can give you a more precise answer!