until and by with future tense

[aysaa]

Hello,

Could you please help me because I couldn't get the difference in the sentences I wrote.

I will have been working by 3:00 pm

I will have been working until 3:00 pm

What is the difference between by and until in here?

Thanks....

 

[5jj]

[Neither sentence is very likely. Are you trying to convey either of these messages;

I will have started work by 3.00pm.
I will be working until 3.00 pm.

?

 

[aysaa]

-By the end of this year he will have been giving private courses for ten years.

-Until the end of this year he will have been giving private courses for ten years.

Can we put 'until/ till' instead of 'by' in this sentence? I couldn't understand the difference between by and until while using 'future perfect con. tense.

 

[5jj]

-By the end of this year he will have been giving private courses for ten years. :tick:
Until the end of this year he will have been giving private courses for ten years.X.

We use by for actions occurring or being completed no later than a future time point.
We use until for actions continuing up to a future time point.