three years; the third year / (education) the third school year / (figuratively) a long period of time, several years

three years; triennial / three years old

to attach

祖父: grandfather / 粗布: coarse cloth

female genitalia; vagina

水素: hydrogen

基礎: basis, foundation, groundwork / 起訴: litigation, prosecution / 稀疎: rarity

木曽: the area around the upper part of Kiso River, west of the Kiso Mountains; a Japanese surname

フッ素: fluorine, fluorine gas

ケイ素: silicon