We spend our lives swimming in a boundless sea of language, from the moment we begin to understand our first words. Being so profoundly immersed allows us to go where we like in this ocean, confident that we know all that is important about how to navigate it. But beware: Even in the relative safety of your own reef or pool, sharks are lurking in these waters.
Familiarity can make us incautious. A headlong plunge into your subject can be a great advantage in getting the ideas out on the page in a first draft, but when you start refining your words and editing them, it's best to start with a clear understanding of what kinds of hazards you may have met along the way.
Locating your subject and verb is a useful first step in the process of finding possible mistakes or bad habits in grammar. In a simple sentence, it's easy to figure out who or what is acting and what is being done. When we say, "Frank and his brothers renovated our kitchen last week," we know the action (to renovate) and who performed it (Frank and his brothers).
But what happens when we say something like "Let's go out Thursday with Connie and Bill"? Here we have to take apart the beginning contraction, which means "Let us." But who or what is the subject here? In this sentence we have a pronoun, us, and a set of proper nouns, Connie and Bill, that could be candidates, but is either of those possible subjects performing the action? Who is letting us go out?
The verb in this kind of sentence takes what is called the imperative mood. It makes a command:
Let us do this.
Go ahead, make my day.
Be sure to take out the trash.
The subject here is implied. It is the entity we wish to perform the action, which in all cases is you, in either the singular or plural, depending on whom we are addressing. What we really mean, when we use the imperative, is:
(You) let us do this.
(You) go ahead, make my day.
Don't (you) bother.
(You) be sure to take out the trash.
So when we casually come out with a suggestion like "Let's go out Thursday with Connie and Bill," we're hoping the action of letting will be performed not by us or by our friends Connie and Bill but by you, the person we're addressing.
Another kind of hidden-subject sentence is even more insidious, and that is the sentence that begins with "There." The subject is present, but it is not the word there. It lingers just out of reach of the unprepared, but if you're careful, you can grab it by the fin and wrangle it.
There is orange juice in the refrigerator.
There are some wonderful sights along the coast.
There have been many strange incidents.
There remained a powerful odor in the air.
The verbs in these sentences are easy to identify: is, are, have been, remained. But the subject isn't where we expect it to be. In this kind of sentence, "There" is a placeholder. It isn't actually doing anything. To find the subject, we have to start with the verb and detect who or what is performing it, or in this case, existing, since the verbs are several forms of "to be" and one form of "to remain," which means to continue existing.
If you take out "There" and reorder the words so the sentence still has the same meaning, the task is simpler, even though the construction doesn't always seem to make as much sense. (Some guidebooks and grammarians tell you not to begin a sentence with "There is" or "There are." In many cases, avoiding such constructions may make for a more muscular style, using the active voice, but on many occasions, this kind of construction is the most natural way to express a thought.)
Orange juice is in the refrigerator.
Wonderful sights are along the coast.
Many strange incidents have been.
A powerful odor remained in the air.
Juice, sights, incidents, and odor are the simple subjects. One reason it is useful to know this is that it may help you avoid using a plural verb for a singular subject, or vice versa, making a mistake like this:
There has been many strange incidents.
The subject and verb may both slip out of sight when you take the opportunity to ask a question, because their order is inverted or mixed up.
How should I know?
Can you believe it?
Wouldn't they be better off not driving to Milwaukee in a snowstorm?
Who ate that bagel?
Often, the subject comes directly after the verb or between the helping verb and the main verb. If you recast the sentence as a statement, you will end up putting the subject in its usual position before the verb:
I should know. You can believe it. They wouldn't be better off not driving to Milwaukee in a snowstorm.
In the last example, though, the subject and verb are in the usual order, because the question word who, a pronoun, is in the right place. If you find it confusing, you can imagine replacing it with a word that who might be standing in for, like somebody or nobody:
Who (somebody) ate that bagel.
Learn to identify the subject and verb in these exceptional cases, and you will be better equipped to dive into deeper zones of composition, while still getting your ideas across to your readers in clear, sparkling terms.