Sentence:  Now, the Subject of either an indicative or a subjunctive Clause is always assigned "Nominative" <WSD>case</WSD>, as we see from:/ (16) (a)   I know [that "they"/"them"/"their" leave for Hawaii tomorrow]/ <font color=white>(16)</font> (b)   I demand [that "they"/"them"/"their" leave for Hawaii tomorrow]/ By contrast, the Subject of an infinitive Clause is assigned "Objective" <WSD>case</WSD>, as we see from:/ (17)   I want ["them"/"they"/"their" to leave for Hawaii tomorrow]/ And the Subject of a "gerund" Clause is assigned either "Objective" or "Genitive" <WSD>case</WSD>: cf./  (18)   I don't like the idea of ["them"/"their"/"they" leaving for Hawaii tomorrow] 
Meaning of the word marked with <WSD> tags:  A specific inflection of a word depending on its function in the sentence.