1.
Can you tell me the difference from using preposition in these sentences:
- I will have to come back by Sunday.
- I will have to come back on Sunday.
the difference from using preposition: BY, ON in time.
2
How long ago .......? we use Present Perfect Tense or Past Simple Tense in this question?
Ex:
How long ago did you come here? or
How long ago have you come here?
Which question is correct?

