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

一戸建[ikkodate] detached house
一本建て[ippondate] (a) single standard
円建て[endate] denominated in yen
経営再建[keieisaiken] management reorganization
建てる[tateru] to build

建て回す[tatemawasu] to build around
建て増す[tatemasu] to extend (building)
建議[kengi] proposition
建具[tategu] fittings such as sliding doors, fusuma, shoji, etc.
建国[kenkoku] founding of a nation

位階[ikai] court rank
位階勲等[ikaikuntou] court rank and honors
一階[ikkai] one floor
音階[onkai] musical scale
下層階級[kasoukaikyuu] proletariat

階下[kaika] lower floor
階級[kaikyuu] (social) class
階級章[kaikyuushou] rank insignia
階級闘争[kaikyuutousou] class struggle