Keep going until you have rubbed through the lid.

Can anyone describe me what is grammaticaly happening in the sentence above?

Antworten

Gelöschter Nutzer

12 Okt 2015

Can anyone describe what is happening grammatically in the sentence above?

"To keep going" is a phrasal verb that means to continue doing whatever you were doing before. In this case it means to continue rubbing. It is used here in the imperative form i.e. a command.

Until is a preposition that means "up to the point in time." The structure of this sentence is Keep going until X. Where X is the condition that has to be fulfilled or met before you can stop rubbing.

"you have rubbed through the lid" is an independent clause (it has a subject and a verb) and can stand by itself as an independent sentence. Here it is used as the condition that, when met, allows you to stop rubbing.

You have rubbed through the lid
[Subject] [verb] [preposition] [direct object]
The use of the perfect tense here (have rubbed) shows that the action (rubbing through the lid) is done to completion before the condition is met.

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lukasz

13 Okt 2015

Polnisch

I have to ask one more thing that is crucial for me here: you said that "you have rubbed through the lid" is a perfect tense, but isn't it that this is Future perfect tense just without "will"?

I mean present perfect tense that expresses future perfect tense. Such like in "he will be tired when he arrives" - we use present tense to express future. Is in my example the same situation?

Gelöschter Nutzer

13 Okt 2015

No, it's not the same situation. We use future perfect in English when we make guesses or assumptions about things. For example:

He will have boarded the plane by now. (He is probably on the plane already)
The store will have closed by now. (I think the store is already closed)

This is just regular present perfect tense. Even though you will rub through the lid in the future, the sentence itself is in present tense (Keep going..)

The use of the perfect just makes it clear that the action is done to completion. You can write it like this as well: Keep going until you rub through the lid.

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lukasz

13 Okt 2015

Polnisch

Oh Gosh :) Are you sure, you haven't mistaken anything? Especially your examples of future perfect? How is it possible to use future tense talking about something what is already done? It doesn't make sense for me.

But the good thing is that I guess I know what you mean. You mean that the first clause ”Keep going" determines a tense of the whole sentence.
If we changed "Keep going" to "You will keep going", then the second clause "you have rubbed through the lid" would be just future perfect without "will". Am I right this time?

Gelöschter Nutzer

13 Okt 2015

Your first question: The use of the future perfect in cases like these is to show your assumption about a situation. You can also express them using present tense:

He is on the plane. (is boarded is unnatural)
The store is closed.

However, the future perfect makes the belief less strong. If you say, "the store is closed" then you are certain that the store is closed, but if you say, "the store will have closed" there is a little bit of doubt. You can just avoid this completely and phrase it "I think the store is closed" or "The store is probably closed" which are more common in conversation than using future perfect.

We don't use future perfect in time clauses that follow words/phrases like until, before, after, when, as soon as, etc. even though the event we are referring to is in the future. We use present tense or present perfect (if we want to emphasize that the action is completed)

Your sentence would still use the regular present perfect tense:
You will keep going until you have rubbed through the lid.

This is not future perfect tense without "will." It is not related to future perfect. You do not use future perfect in time clauses:

I will watch a movie after I have finished my homework (O)
I will watch a movie after I finish my homework (O)
I will watch a movie after I will have finished my homework (X)

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lukasz

13 Okt 2015

Polnisch

I know this is not future perfect tense, the same as in "He will be tired when he arrives" is not used future simple after "when".
But what I mean is that between "He will be tired when he arrives" and "You will keep going until you_have rubbed through the llid" is the same issue - the words "when" and "until" changed future tense to present and that's why you tell me it's not future. I mean grammatically it's present but in life it's future.

About the usage of future perfect as a guess, I think it's very advanced grammar, so I won't care of it :)

Gelöschter Nutzer

14 Okt 2015

Yes. It is in the future, but it is present tense grammatically. The future perfect is hardly used in AmE in my experience, and you can just rephrase it more simply anyway. :)

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lukasz

14 Okt 2015

Polnisch

I'm glad that we've reached an agreement :)
I just wanted to know if the way I imagine this is good. In a nutshell, for me this is a Future perfect Tense expressed by Present perfect Form (just logic doesn't let me think of something what hasn't happened yet or maybe better something what WILL happen as a present tense) (if grammar says it's present tense, they should change it!! :D ) and I'm sorry for making it so complicated :)