uponの意味
I am 34, with a Ph.D. and a successful, happy life. I am regularly mistaken for being much younger—often a college student. (I live in a city with many colleges, which probably doesn’t help.) Though I’ll be “thankful for this someday,” according to many well-meaning but semi-irritating strangers, I have struggled for years to think of an appropriate response to people’s surprise upon learning my actual age.
uponはどのような意味でしょうか?onと置き換えられるのでしょうか?よろしくお願いします