“WILL” or ”BE GOING TO” or ”BE –ING”？

[Shinya Maki]

Which is correct?

If Mr. Smith has already promised me on the phone that he will bring the book and lend it to me next Monday, then I can say to my friends, “( ) the book from Mr. Smith next Monday."

1. I’ll borrow 2. I’m going to borrow 3. I’m borrowing

[Pete]

Which is correct?

If Mr. Smith has already promised me on the phone that he will bring the book and lend it to me next Monday, then I can say to my friends, “( ) the book from Mr. Smith next Monday."

1. I’ll borrow 2. I’m going to borrow 3. I’m borrowing
Number 3 is best in this situation. It gives the idea that you and Mr. Smith have arranged for this to happen.

Number 2 would also be possible; it neutrally predicts the future event.

Number 1 doesn't sound right here; it gives the idea that this is what you intend to do, and your point really isn't to show your current intention.