I take 12-3 The subject of the verb should be in the subjective case. The direct object of the verb suspected should be in the objective case. This becomes clear if you restructure the clause. The subject of the verb knew should be in the subjective case. The modifier of the gerund being should be in the possessive case. The object of the verb am teaching should be in the objective case. To test for the correct pronoun, try restructuring the clause. Although subjects are ordinarily in the subjective case, subjects of infinitives are an exception to the rule. The subject of to defeat should be in the objective case.