I will finish my himewiork by 3 o'clock. I will have finished my homewok by 3 o'clock

[wotcha]

1. I will finish my homework by 3 o'clock.

2. I will have finished my homework by 3 o'clock

3. I will finish my homework at 3 o'clock.



My question here is what I can answer my students if they ask

how the future tense and future perfect are different.


Is sentence 1 and 3 grammatical?

Will it be safe to say sentence 1 and 2 are interchangeable to my students?

 

[5jj]

1. I will finish my homework by 3 o'clock.
2. I will have finished my homework by 3 o'clock
3. I will finish my homework at 3 o'clock.

My question here is what I can answer my students if they ask how the future tense and future perfect are different.

[STRIKE]Is[/STRIKE] Are sentences 1 and 3 grammatical?

Will it be safe to say sentences 1 and 2 are interchangeable to my students?

All three are grammatically correct. #1 and #2 are for practical purposes interchangeable.