Vocabulary consisting only from characters you are able to read
難問
なんもん
perplexity, difficult question, difficult problemsuru
合宿
がっしゅく
lodging together, training camp, boarding housesuru
中
なか
inside, middle, amongjlpt5
上達
じょうたつ
(1)improvement, advance, progress, (2)communication of opinions of the general populace to those of high rank suru
従来
じゅうらい
up to now, so far, traditional, existing (e.g. equipment)mix