I wouldn't say "I think so". You either have or haven't been to Africa.
Try: "Yes, but it was a long time ago, so I don't remember much about the trip."
Have you been to Africa? I say:
I think so, but It must've been a long time ago, because I don't remember much of the trip.
Can this be said?
What if you really don't remember?
How about the second and third part of the sentence - It must've been a long time ago, because I don't remember much of the trip.
Why doesn't it make sense?
But what if I truly went to so many places with my parents as a kid that I don't remember if I've been to Africa or not... Kinda like how I've lost track of many places I visited when I was a very young kid 20+ years ago?
Do you talk to your parents? Could they fill in the details? This whole thread is becoming absurd. A trip that never happened could not have been a long time ago.
***** NOT A TEACHER *****
The following dialogue is based on actual facts in my life of 77 years here in California:
Mona: Have you ever been to Arizona? I'm writing an article for the Senior Citizens [pensioners] Monthly.
James: I don't know.
Mona: What do you mean that you don't know?
James: Well, I think that I remember hearing something about my parents having taken me to Arizona on a short visit when I was an infant. But I certainly do not remember any such visit, and maybe I am even imagining that I ever heard such a thing. Therefore, for all intents and purposes, I can honestly say that I have never been to Arizona.
Mona: OK. I'll report that you have never been to Arizona.
Last edited by TheParser; 23-Oct-2014 at 17:17. Reason: vocabulary