難問: difficult problem / 南門: south gate

これは何ですか: what is this?

to say goodbye

understanding quickly; sharp; keen / quick-start guide

easy to understand / (of a person) able to be read like a book

to be evident / to be obvious / to understand completely

分かり切る: to be evident, to be obvious, to understand completely

You'll be convinced if you listen to me.

Alternative form of クレイオー (Kureiō, “Clio”) (the Muse of history and heroic poetry)

becquerel