Student or Learner
10:00 - [...] because hopefully I've explained them, but if ... wasn't clear remember you can [...]
(British English pronunciation lesson: "Twenty-one reasons why English is hard to learn; YouTube)
Would you be so kind to tell me whether he said 'they' or 'that'?
He said 'it', I think. I suspect that he was about to begin 'they', thinking of '21 reasons', but changed mid-thought to 'it', thinking of his explanation.