一も二も無く[ichimonimonaku] unhesitatingly
一言二言[hitokotofutakoto] a word or two
一石二鳥[issekinichou] killing two birds with one stone
一二に及ばず[ichininioyobazu] right away
一姫二太郎[ichihimenitarou] It's good to have a girl first and then a boy

うり二つ[urifutatsu] as alike as two melons (two peas in a pod)
黄道十二宮[koudoujuunikyuu] twelve signs of the zodiac
二度[futatabi] again
最小二乗法[saishounijouhou] least-squares method
三十二分音符[sanjuunibuonpu] 32nd note

彼所[asuko] there (place physically distant from both speaker and listener)
其れ所か[soredokoroka] on the contrary
所が[tokoroga] even so
所縁[yukari] related to (some person or place)
ジェット推進研究所[jettosuishinkenkyuusho] Jet Propulsion Laboratory

悪所[akusho] dangerous area
案内所[annaijo] information desk
育種所[ikushujo] (plant) nursery
一所懸命[isshokenmei] very hard
印刷所[insatsujo] press

一箇年[ikkanen] one year
一箇[ikko] piece
何箇月[nankagetsu] how many months?
箇月[kagetsu] (number of) months
箇条[kajou] items

三箇日[sanganichi] first three days of the New Year (January 1st to 3rd)
信仰箇条[shinkoukajou] articles of faith
二箇所[nikasho] two parts
別箇[bekko] another