Re: CELTA - confused about the most common answer regarding "I've been to the bank...
"I was at the bank yesterday" only refers to location.
"I went to the bank yesterday" suggests a visit which involved some kind of financial transaction.
To be fair, it's more a difference in our comprehension of what happened than anything else. The phrase "to go to the bank", in BrE at least, is taken to mean "to visit the building or institution known as a bank and carry out out some unspecified banking transaction".
Q - Where were you yesterday when the bomb went off at the church?
A - Fortunately, I was at the bank.
Q - What did you do yesterday?
A - I went to the bank, then I met a friend for coffee.
Remember - correct capitalisation, punctuation and spacing make posts much easier to read.