Here is a short passage that can help us review briefly the tenses of verbs in English. The term tense refers to the time when the action of a verb occurs, and you would think there wouldn’t be much to talk about because there’s only past, present, and future. But as these three sentences will illustrate, our perception of time weaves itself subtly through our memory, and what we call time can have many fine shades of distinction. In this passage, a father is talking to his young son: I had explained to him that the sun always rises in the east. But he told me no, and said he was sure it always comes out over there, pointing to where it was just then high in the sky to the south. “It doesn’t move, it just shines,” he said.
Let’s begin with this quick overview. English has six tenses, and what we know as past, present, and future fall into two large groups called simple and perfect (the term perfect means complete, or finished). There is a simple present, a simple past, and a simple future, and there is a present perfect, a past perfect, and a future perfect. The verb rise in our passage, for example, would look like this in these six tenses: the sun rises, rose, and will rise; and the sun has risen, had risen, and will have risen. One sure way to recognize a perfect tense is by seeing some form of the verb have, which always serves as an auxiliary verb to construct those three tenses.
If we examine, then, the verbs in the first sentence of our illustration, we find had explained and rises, and according to the scheme of tenses we just reviewed, we know that had explained is past perfect and rises is simple present. Because time can be so fickle, it is important to coordinate the tenses in a sentence accurately. The rational frame of mind we are in when we think and write does not like change; it wants stability and coordination above all else, and that means we have to be aware not only of chronological time (the real time of yesterday, today, and tomorrow), but of relative time as well.
The past perfect tense in the clause I had explained points, for example, not merely to an event in the past, but to an event that occurred even before another event in the past. That is the special function of the past perfect; it is a relative tense, and that means that it has to work in coordination with another verb in the past tense. But where is that other verb in this first sentence of the passage? Since we have already identified the only other verb in the sentence (rises) as simple present, we have to look elsewhere for the coordinating verb, and it is not until we read the first verb of the next sentence, told, that we find the verb with which had explained works. The verb told is simple past, and that independent verb holds the time of the passage together.
But why, then, is the verb rises in the simple present? Shouldn’t this too be in the simple past if the coordination of tense is so important? To say that the sun always rises in the east is not meant to point to an event currently underway in the present moment; it means instead to say something about the way the world is constructed, to indicate an enduring fact of our experience. Present tense verbs, in other words, can point to what is always the case, not just to what happens to be a fact at the present moment. And that’s what gives the little boy’s retort a little zest: with all his own present tenses (comes out, doesn’t move, just shines), he’s challenging the father’s rational and matter-of-fact world with an imaginative world of his own, leaving us to wonder just where the line really is between the two.
Recognizing the changes in tense across a passage, then, is not just a matter of grammatical correctness; it can also be a way to see other more subtle meanings that might be folded into a passage. And that might be enough to make the complicated topic of verb tense worth the figuring out.