The grammatical case in English language is the mode of the sentence of the parts of a sentence which help us determine what part it is playing in that particular sentence. The grammatical case is divided into various sub cases which I have discussed in my other articles.
I miss him.
As a rule we know that in order to identify a direct object in a sentence, first identify the verb or action word of that sentence, and then ask the question what? or who? of the verb. The answer of this question will lead you to the direct object.
In order to see if the case of the noun/pronoun is accusative in the above example you first will identify the verb. The clear verb or action happening in this sentence is rang. Rang what? Doorbell. Thus, doorbellis the noun existing as accusative case of English grammar in this sentence.