Final answer:
If a preposition has an object in the genitive or dative case, you should not use an indefinite or definitive article before the preposition. Pronouns before gerunds should be in the possessive case, and pronouns as objects of prepositions should be in the objective case.
Step-by-step explanation:
If the object of a preposition is genitive or dative, do not precede the preposition with an indefinite article ('a' or 'an') or a definitive article ('the').
When discussing pronoun case, it's important to use the correct case for the pronouns in a sentence based on their grammatical function. The possessive case should be used before a gerund. For example, 'The rental agreement depends on your approving the lease terms.' This is correct because 'your' is showing possession over the action of approving.
Passive voice can be eliminated by making the subject the doer of the action, but note that sometimes passive voice is the preferred construction, especially when the object being acted upon is more important or the doer is unknown. Prepositions require pronouns in the objective case, as in the sentence 'Give the tickets to whomever you choose,' where 'whomever' is the object of the clause.