Tweet of the Week #45: The One Thing That Always Happens to Japanese Exchange Students in America blog.gaijinpot.com

And if you needed a reason as to why Japan should be high on your list when scouting study abroad opportunities, know that Japan recently ranked as the No.
2 study abroad destination in Asia AND No.1 for teaching quality, with three universities in the worldwide Top 100.
How to use the expression: ことがあるWhen you study Japanese, you’ll quickly learn that the language barely has tenses, certainly not as many as in English.
When preceded by the past tense, the expression ことがある indicates something that took place in the past.
You are not focusing on when it happened or the context (you would then just use the past tense!)