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  • Hi, everybody.

  • Welcome back to www.engvid.com.

  • I'm Adam.

  • In today's video we're going to look at the prepositions: "by" and "until".

  • We're going to look at the differences between them, and how to use them, and what specific

  • meanings they each have.

  • We're also going to look at the expression: "by the time", as another way of using "by"

  • or whatever situation, and this one: "no ________ than".

  • Now, the reason why I left this blank is because you can actually put quite a few words in there.

  • We're going to look specifically at: "no later than" to replace "by" and "until", but for

  • now I want you to also understand that there's other uses for it, and I'll give you some

  • examples of those.

  • Now, before I start I will say Emma did a very good lesson about "by" and "until".

  • Mine is a little bit different because I'm going to show you some other situations where

  • you will use one or the other.

  • Okay?

  • So we're going to start by figuring out: What's the difference between these two?

  • So look at our example sentences.

  • I'll get to our little time map in a second.

  • "I'll be at the office until noon.", "I'll be at the office by noon."

  • Now, first of all, let's assume the average workday is about...

  • Is from 9 until about 5 o'clock, but I have some...

  • I have some meetings in the afternoon so I will have to leave the office.

  • But if you want to meet with me, I'll be there until noon.

  • What does that mean?

  • It means that I will arrive at the office at the usual time, 9 o'clock, and I will stay there.

  • So my stay at the office will continue until noon.

  • At noon I will leave.

  • Okay? So this is when we're using "until".

  • Now, before I get in...

  • Into that again, let's look at the second one.

  • "I'll be at the office by noon."

  • So, here, we're looking at somewhere in this time, but not later than noon I will arrive

  • at the office.

  • Okay? Now, what's the key difference between these two?

  • Well, one, something continues.

  • An action starts, continues, and it ends at that time mentioned after "until".

  • So both of them have an end time.

  • You could even say a deadline, but that's for other uses.

  • There's an end time.

  • And that end time is noon.

  • Okay? Something will happen at noon.

  • Now, in the case of "by", it could happen before.

  • In the case of "until", only one thing will happen.

  • But the key to remember: When we use "by", we're looking at a finite action.

  • This arrive is a one-time thing. Right?

  • It'll... It can happen here, it could happen here, it could even happen here.

  • With "until" only here will I leave.

  • Okay?

  • Now, what's the difference, another difference that we have to think about?

  • Is not only the continuance of an action and the finite situation of an action;

  • here, we're looking at something ending.

  • My time at the office will end.

  • Here, something can end or start.

  • So if you want to meet me, I'll be in the office by noon, so you can meet me

  • from noon until 5.

  • So the start time, the earliest time you can meet me is noon.

  • The latest time you can meet me is just before noon because I'm leaving at noon. Right?

  • So that's one thing to keep in mind.

  • The... Basically the implied situation.

  • Now: "I'll be at the office by noon and I'll stay until 5."

  • You can use both of them in one sentence.

  • Sometime in here I'll arrive, and then from 12 till 5, I'll be at the office.

  • So, what's the key?

  • Now I hope you basically notice this.

  • What's the key difference in these two sentences, is it the preposition?

  • Yes.

  • Different prepositions, different meanings.

  • But what I hope you realize is that the difference is in the verb "be".

  • Why?

  • What does "be" mean here, and what does "be" mean here?

  • "Be... I'll be at the office until...

  • Until noon", means I will stay at the office until noon.

  • So this situation will continue.

  • Here, "be" means arrive.

  • "I will arrive at the office by noon."

  • So, one point here in this time...

  • Timeframe I guess you could call it, something will happen.

  • Continued, finite.

  • "Finite" means it's a one-time action and that's it, it's finished.

  • So that's a very important thing to remember with "by".

  • Okay?

  • "By", and we also think about: "at", "on", or "before".

  • So, "at" for time.

  • This is a little review of prepositions.

  • "At 5 o'clock", "on Friday", "on day",

  • so: "At 5 o'clock or before.", "At noon or before.",

  • "On Friday or before."

  • Okay? "Until"...

  • Now, we don't use this preposition "to", but something continues to the end time.

  • Okay?

  • So that's one way... Another way of thinking about these two in terms of: What's the difference?

  • "By" or "before" continue "to".

  • Okay?

  • We're going to look at a few more samples, and you'll get a better idea of when to use

  • "by", when to use "until".

  • Okay, so let's look at some more examples and I want to come back to this idea of finite

  • actions. Okay?

  • "Finish" is a finite action.

  • Now, just to clarify, again: What does "finite" mean?

  • It means it's a very limited time.

  • It doesn't go on for a long time.

  • So if you're going to finish your homework, it means last question answered, done, finished.

  • You can't be finishing for a long time because the verb "finish" doesn't extend; it's done

  • or it's not done.

  • Right?

  • So: "I'll finish my homework until 5."

  • Now, a lot of people will say this, they will write this, but technically it's not correct.

  • "I'll finish my homework by 5." is okay because it's a one-time situation and it'll happen

  • at 5 or before, at some point in that time.

  • So, how would you fix the first sentence?

  • Two ways.

  • One: "I'll finish my homework at 5."

  • That's one way.

  • If you know you're going to be done at 5 you can say that.

  • But the better thing to do is to change the verb, make it a non-finite verb.

  • "I'll work on my homework until 5."

  • Means work, work, work, time goes on, work, work, work, time goes on, 5 o'clock, okay, I'm done.

  • Finished, not finished, not important.

  • If you finished, great.

  • If you didn't finish, that's fine.

  • 5 o'clock is your end time, then you will finish later if you didn't finish by 5.

  • Okay.

  • Now, another thing to keep in mind: We can use both prepositions with any tense.

  • You can talk about the past, you can talk about the future.

  • But when we're using perfect tenses, we use the "by" preposition.

  • Let's look at examples.

  • "I'll have completed my tasks by 5 o'clock."

  • "Will have completed", this is your future perfect.

  • The future perfect often makes use of "by".

  • Okay? We can also talk about the past perfect.

  • Now, here, I'm starting to introduce: "By the time".

  • "By the time" has the exact same use or the exact same function as "by", except that now

  • instead of saying: "By 5 o'clock", "By Tuesday", "By next year",

  • I'm giving you a more general time.

  • And then I'm identifying that time.

  • Right?

  • So I can be more generic...

  • General. I can say anything.

  • "By the time we're through", I don't have to give you a specific time, I can give you

  • a specific situation.

  • "By the time he arrived", so now the time is when this action happened.

  • What time of the day?

  • I don't know. Not important.

  • "By the time he arrived", so I have my adjective clause to identify the time, and then I have

  • my next clause: "She had already left."

  • So, because at this time he arrived...

  • "By this time" means at this time or before. Right?

  • So if it happened before, I must use the past perfect to show the relationship in time.

  • Okay?

  • By the time he arrived, she had already left.

  • "I'll have completed my tasks by 5 o'clock."

  • So 5 o'clock, they're done.

  • Okay.

  • Let's look at "until" just to show you there could be past, or present, future, etc.

  • "She waited in the lobby until he arrived."

  • So she waited, waited, waited, waited, waited.

  • Oh, there he is.

  • So, again, you don't have to use a specific time.

  • You can use an actual clause, and then there...

  • This is therefore a clause marker, an adverb clause marker, subordinate clause.

  • "Until he arrives, she..."

  • "She can", this is an "n".

  • "...she can wait in the lobby.

  • Until he arrives, she can..." so we have a present.

  • "Until he arrives," keep in mind this is still an adverb clause now we're looking at.

  • You can't use "by" as a clause marker, as an adverb clause, but you can use:

  • "By the time" with an adjective clause or "until" with an adverb clause.

  • "Until he arrives, she will wait in the lobby."

  • Present simple, future.