Is it okay to change "will have been ~ing" into this structure?

[eggcracker]

Hello. I saw a article about future participles.
By the end of next week, Emma will have been seeing Luke for three months. From:http://www.usingenglish.com/articles...n-english.html

Is it okay to replace the sentence put in bold letters with the sentence below(By...,...will keep...)? I understood the meaning, but I want to change the sentence into common usage.
By the end of next week, Emma will keep seeing Luke for three months.

[Rover_KE]

Definitely not.

The original sentence is already in what you call 'common usage'.

Rover

[eggcracker]

Thank you Rover. But, doesn't the sentence[By the end of next week, Emma will keep seeing Luke for three months.] contain the same meaning as the sentence put in bold letters?

[emsr2d2]

Thank you Rover. But, isn't the sentence[By the end of next week, Emma will keep seeing Luke for three months.] contains the same meaning as the sentence put in bold letters?

No, not at all. "Emma will keep seeing Luke for three months" means that she will continue to see him for another three months after the end of next week. Your original sentence means that by the end of next week, Emma and Luke will have already been a couple for three months".

[eggcracker]

Then [By the end of next week, Emma will keep seeing Luke for three months.] will have to be [Emma will keep seeing Luke for three months even after the end of next week] if I want to avoid confusion because of jarring words in the sentence such as By, will keep seeing, although it may be a opposite meaning to the original sentence. Am I right?

[Rover_KE]

If you want to avoid confusion, don't bother trying to change the original, perfectly good sentence.

Rover

[Barb_D]

What are you trying to do here? What is the point of taking one sentence, and then creating two equivalent sentences with a completely different meaning from that first one?

I got here Monday. Today is Tuesday. I plan to leave Saturday.

By Thursday, I will have been here three days.
By Thursday, I will only have two more days to stay.

[eggcracker]

I did it because of my fear of causing confusion.

[Barb_D]

But the first sentence had a specific meaning. It was not confusing. If that is what you need to express, how does it avoid confusion to create a sentence with an entirely new meaning??

[eggcracker]

I was half sure about the future perfect usage because I didn't have the concrete information about the structure like that before, and I had a memory that some person who was asked about 'will have ~ing / will have ~ed' by me told that the forms like that is antiquated in present English. Now I'm 99 percent sure the usage is common though. Well, I will be sure about the usage 100 percent soon after searching some more examples.