Our final lesson in the verb form module, sequence of tenses. This can be a tricky topic. Suppose for example, thing number one happened last week, that's a past event. Thing number two happens this week, that's a present event. Thing number three will happen next week, that's a future event. So suppose we have these three things we're concerned about. Read full transcript
Right now, we're talking about past, present, and future, no problem. Similarly, it's no problem to describe someone reporting these events in the present. Joe tells us that Thing number one, happened last week, Thing number two happens right now, and Thing number three will happen next week. Here we're just using simple past, simple present, simple future.
So these are simple verb tenses so far, so good. There's no problem here. Here's where it gets tricky. Now, suppose someone in the past reported on events in their past, their present, and their future. So last year, Joe told us Thing number one, something, something about happening, or happened, or something like that before that time.
Thing number two, something about happening or happened, or was happening, or will be happening, something right then. And then Thing number three, similarly other form of the verb after that point in time. We wanna know what form of the verb should go in those three blanks. This situation, people in the past describing events in their past, their present, and their future, this is the sequence of tenses situations.
Here are the rules. For the speaker's present, we use the simple past tense. We could also the past progressive if we wanted to show ongoing activity. For the speaker's past, of course that's something before another past event, so we used the past perfect tense. And for the speaker's future, we use the conditional tense.
Just a reminder, the conditional tense we use the auxiliary verb would. Would happen, is a conditional tense verb. So in our description of the three things, Joe said that Thing number one, the past event, had happened before. That Thing number two was happening, they we're using the past progressive to show ongoing acting, action.
And Thing number three would happen, conditional tense, after that point in time. So the sequence of tense rules are used not only for saying, but also for thinking, arguing, believing, basically any verb that can take at that clause. If the verb happens in the past, we have to use the sequence of tense rules. Here's a slightly more GMAT like sentence.
Geologist Charles Lyell believed that the theologians of previous centuries had vastly underestimated the age of the Earth and that evidence would justify a much older Earth then was previously suspected. This is an example of the correct application of sequence of tense rules. So, the geologist is in the past, he's believing, that action is in the past. Before him were the theologians, so their action has to be past-perfect, before another past event.
So in Charles Lyell's past, we use past-perfect for that. For Charles Lyell's future, we use the conditional tense, would justify. Again, this is a totally correct application of the sequence of tense rules. Remember to apply the sequence of tense rules, the speaking or the thinking or the believing must occur in the past.
It's perfectly correct to say, he says that she will come. So that's present reporting and then we use ordinary future tense of the verb. So, we just use ordinary tenses when the reporting is in the present. It's only when the reporting is in the past that we use the sequence of tense rules. He said that she would come.
That is also 100% grammatically correct. We run into problems when we start swapping around which we use with which. So for example, he says that she would come. So that's not an ordinarily correct sentence. That might be correct if what he is reporting is conditional expression of some kind.
But that really changes the meaning. He said that she will come, that is just 100% incorrect. So beware of swapping these things around using the sequence of tense rules in the present, or using simple tenses when the reporting is in the past.