Subjects

Subjects are always nouns, the noun or nouns in a sentence which do the action represented by the main verb, for example, “I teach.” “I” is the subject of the verb “teach,” because “I” is doing the action of teaching. “You will learn.” “You” is the subject of the verb “learn.” The time when the action takes place ─ in this case, at some point in the future ─ doesn’t matter. “You” is still the subject of the sentence even if the action hasn’t happened yet. “We studied.” “We” is the doer of “studied,” thus the subject of the sentence. Here, the verb is past-tense but that doesn’t affect the subject. “We” are still the actors who performed the action of studying even though it happened long ago. “It isn’t.” “It” is the subject of “isn’t.” The subject can also be a noun which is said not to be doing the action of the verb if the verb is modified by a negator like “not, never, in no way.”

In other words, subjects can also be the non-doers of the verb action if the point of the sentence is to say outright that the subject didn’t do something, as in “she cannot forget.” “She” is the subject of “forget,” even when “she” isn’t actually forgetting because she can’t, according to the sentence. So even if “she” is a non-doer, grammatically she’s still the “doer,” the subject. One last example: “they must leave.” “They” is the subject, in this case, the need-to-doers of the verb action “leave.

Direct Objects

A direct object is any noun which receives the action of a verb, for instance, “I see you.” “I” is the subject, “see” is the verb, and “you” is the direct object because “you” is the object of the seeing in this sentence. That is, it’s on the receiving end of the seeing that the subject (“I”) is doing here.

Here’s another example: “You make lots of money.” What’s the verb here? “Make.” Who’s doing the making? “You,” so that’s the subject, and the thing or things that are being made by you are … what? “Lots (of money).” “Of,” you’ll recall from the second grammar preview, is a preposition, and its object, the OP here, is “money.” So “of money” is a prepositional phrase. If “money” is an OP, it can’t also be a direct object. One noun can’t do double-duty in a sentence. That’s the rule. So you can always rule out an OP like “money” here as a direct object. The direct object here is “lots” and “lots” alone. Of course, “lots” and “of money” really mean the same thing when you put them together, but meaning and grammar aren’t always exactly the same. Grammatically, these words function in very different ways. So even though they share one meaning, “lots” is the direct object and “of money” is a prepositional phrase.