If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content
Current time:0:00Total duration:2:50

Shifts in verb tense | Worked example

Video transcript

- [Instructor] Daylight savings time was not adopted in the United States until 1918, but the basic idea for such a system has been proposed centuries earlier in an essay by Benjamin Franklin. So let's go through the answer choices. Let's look at the comma. Is there anything that strikes us as incorrect about the use of this comma? So we've got daylight savings time was not adopted, this is an independent clause, here's a comma, here's what we call a coordinating conjunction, but. I would say this comma is being correctly used to join these two independent clauses. The basic idea for such a system has been proposed, that's an independent clause. Daylight savings time was not adopted, that's an independent clause, comma, plus this kind of conjunction is completely kosher, cross that off. B, such a system. This underline is testing whether or not this is a conventional expression in English, such a system, or a kind of a system. It is, so this is fine. Answer C, has been proposed. Now here's the error, it pops right out at me, is has because we've got other time clues in this sentence like 1918 and was and centuries earlier. This is a shift in verb tense question. And when we've got one of those, we wanna look for time clues. Right, because this is in the present tense, this non-underlined portion is in the past tense, but 1918 and centuries earlier indicate that we should be using the past and not the present tense. If you see what looks like a common error, that's the flaw. The sentence only has one. The test is not trying to trip you up. For an error ID question like this, you don't even need to think about how you would fix this sentence. I can tell ya how we'd do it, we'd change it to had been proposed or was proposed. Either of those would work. But for the purposes of an error ID question, you don't need to think through how you would fix it, or even necessarily why it's wrong. You just need to know, oh, that's incorrect, flag it, bag it, and tag it, and move on. Let's go through why earlier is not our choice. So earlier is being correctly used as an adverb that modifies this entire verb phrase. So had been proposed earlier, or has been proposed earlier, this is a conventional usage of an adverb. And since we have identified an error, we can cross out no error. C is our answer. So if you're looking at an error ID question like this that's got those five underlines, you're looking for the obvious error. And if you see something pertaining to time, and you have these time clues, pay special attention to the verbs and their tenses. And if those tenses are not aligned for some reason, that's your error.