Yeah, I just got into one of those embarrassments last evening with my adult students. This time it was with the verb 'to ski.'
First I thought it had two 'i' s but was corrected. It has just one 'i' except in it's present continous form. Then I was asked the past simple form of it. I got stuck for a moment and then decided to guess it 'skied.' I wrote this on the board and told them that I wasn't sure if it was true and that I would check and comfirm the next day. A smart guy had one of those complex electronic dictionaries in class and fished out the word in all its forms. The past simple has two acceptable forms 'skied' and another strange form 'ski'd.' They all praised me on my lucky guess. A lucky hero I was last evening just as I could have turned out to be a dull teacher.
Oh, this profession of ours!!!