- [Instructor] Mae Jemison, the first Black woman to travel in space, is not only an astronaut, but has also worked as a college professor, a bioengineer, and she made a guest appearance on Star Trek: The Next Generation. So just by looking at the length of this underline and briefly glancing at the answer choices, we can tell this is not an error ID question, this is instead, a revision question. So what that means is that this underlined portion here, which is the same as this answer here, most likely contains an error, a four out of five chance that this contains an error. All these choices are likely going to have a similar kind of error, and the correct choice is going to correct that error. So let's see if we can find an error in this underlined portion. So we've got as a college professor, a bioengineer, and she made a guest appearance on Star Trek: The Next Generation. There's nothing grammatically incorrect about this underlined portion, but what's going on here is a problem in parallel structure. And parallel structure is just when you have a list of things, they should all be the same type of thing. Let me explain by analyzing the sentence. So a college professor, that's a noun, that's a noun phrase. A bioengineer, that's a noun. And she made a guest appearance on Star Trek, that's its own entire clause. We've got a subject here, we've got a verb here, we've got a direct object here, we've got this long prepositional phrase. And it looks like all of these answers have the prepositional phrase in them, they all have on Star Trek: The Next Generation in them, so I'm just gonna cross out all of those, so we don't even have to think about that, like every answer ends the same way. So that must not be part of the error. So what this suggests to me is we've got noun here, noun here, and then whole clause. That's not parallel. The classic, literally classic example of parallel structure is Julius Caesar saying, I came, I saw, I conquered, right? Parallel, three little sentences, I verb, I verb, I verb. That's parallel. So okay, so A contains an error, 'cause it's noun, noun, clause. So whatever we're looking for, we're looking for a list of three items that are all consistent with one another. So let's look at option B, Mae Jemison has also worked as a college professor, that's a noun; a bioengineer, that's a noun; and a guest actress, that's a noun. Okay, that one's pretty promising. Let's star that, we'll come back. All right, answer C, as a college professor, opening her own bioengineering firm and a guest actress. So we've got this noun here, for college professor. We've got this thing that is called a participle, which is sort of when a verb behaves as a noun here. So I'm gonna write P. And we've got noun again. So this isn't the same, right? And also we've got this as in the beginning here, as a college professor, worked as opening. Worked opening kind of makes sense, that's fine, but worked as opening isn't a conventional expression. So in addition to not being consistent, noun, participle, noun, we also have this nonstandard phrase, as opening. So I'm going to cross that off and say, that's not our choice either. Move on to answer D. Teaching college, there's another one of those participles again. Opening her own bioengineering firm, another participle. And she made a guest appearance on Star Trek: The Next Generation. Now this is the same error as the original sentence, right? Because this is its own clause. She, subject; made, verb; a guest appearance, there's our direct object. This is its own clause, its own little sentence hanging out inside this list. And that's not parallel. Finally, answer E, as a college professor. Okay, so we've got a noun here, to be a bioengineer, which is an infinitive verb, right, this is the to form of a verb. And as a guest actress, noun. We've got noun, verb, noun, and that's not parallel. Which brings us back to answer choice B. I'm gonna clean this all up a little bit, get rid of the Caesar quote. So we've got college professor, noun; a bioengineer, noun; and a guest actress, noun. Noun, noun, noun, three equivalent items within the same list structure, this is parallel. So that's our answer. And when you're looking at a revision style question, and you see a list, one of the things you can do is determine whether or not the items of that list are all of the same type. Are they all nouns, are they all verbs? You know, if they're all verbs, are they all conjugated the same way? And if they are, you've got a different problem. But if they aren't it's probably a parallel structure issue. And finding the answer choice that resolves the error is going to be the answer that you want.