It’s/That’s very kind of you, but….
A: I can give you a drive home.
B: Thank you. That’s very kind of you, but I can take the train.
I really shouldn’t.
A: Come on, stay for another drink!
B: I really shouldn’t. I have to get up early for work tomorrow.
I think I’m going to pass on it.
A: I can give you a better discount if you pay for the first 3 months.
B: Hmmm, I think I’m going to pass on it. Thank you, though.
Let me sleep on it.
A: Do you think want to go camping with us?
B: I’d really like to but I don’t have much money. Let me sleep on it, though.