10 Grammar Rules Every Teacher Should Know

Rule #3 I [is not an] Object!
Let’s analyze one sentence closely:

Subject Predicate with Prepositional Phrase

Object
The red car hits a huge pothole by the curb.

“Pothole” is the object of the verb: it is the thing affected by the action. Objects of verbs usually answer the question “what?” as in “The red car hit what?” Objects of prepositions work the same way. There are two problems with objects. The first is that not all nouns in the predicate are objects. For instance, this sentence seems to consist of a subject and predicate with an object:

The red car is a fast vehicle.

After all, there are two nouns and a verb in between just like our example above, right? Also, “vehicle” answers the question “what?” very nicely. So, what’s the problem? Latin is the problem. Here’s the grammatical [il]logic for why “vehicle” isn’t an object:

The Latin derivative verb “to be” (is/was/has been/had been) acts like an equal sign; it indicates that a secondary noun is the same as the subject. Thus, this noun is also a subject and not an object. Other verbs, on the other hand, involve the subject in an action. Thus the secondary noun is being acted upon and is an object.

You’re probably wondering why anyone but Hamlet should care about this “to be” dilemma. It becomes important because of the second problem with objects: case. You can also thank Latin for this one. In Latin, you mark all nouns with a case. In English, we have only preserved cases in pronouns. Do these look familiar?

who/whom she/her I/me
he/him we/us they/them

• 
  The first of each pair is the subject case. You use this whenever the pronoun isn’t an object.
  
• 
  The second of each pair is—you guessed it—the object case. This is used whenever the noun is the object of a verb or of a preposition.
  

Here’s how it works:

Subject Verb Object

He hit me
(not He hit I—“me” is the object of a verb)

Subject Verb Preposition Object

The car drove over her
(not over she—“her” is the object of a preposition)

You’ve been doing this without even knowing you were doing it, right? What messes everyone up is “to be.” Perhaps you’ve heard someone answer the phone with this sentence:

This is she…

Seems wrong, doesn’t it? You want to say “this is her.” But, “her” is the object form and “to be” doesn’t take an object. Thus “she” must be in the subject form. See? This rule is why you should never say:

Whom is it? or It is whom? (WRONG!)
Yet, it is correct to say:

You ran over whom in your car? and To whom did you report it?

“Whom” is an object in both these cases.

Short Cut