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

いい年をして[iitoshiwoshite] (in spite of) being old enough to know better
亥年[idoshi] year of the boar
一箇年[ikkanen] one year
一周年[isshuunen] one full year
一年以内に[ichineninaini] within a year

一年間[ichinenkan] (period of) one year
一年生[ichinensei] annual (plant)
一年草[ichinensou] annual (plant)
一年ぢゅう[ichinenjuu] all year round
一両年[ichiryounen] (a) year or two

お生憎様[oainikusama] that's too bad (ironical)
御誕生日おめでとうございます[otanjoubiomedetougozaimasu] Happy Birthday
隣の芝生は青い[tonarinoshibafuhaaoi] the grass is always greener on the other side
生きがいい[ikigaii] fresh (e.g. fish)
コンピューター援用生産[konpyuutaaenyouseisan] computer-aided manufacture

委託生[itakusei] scholarship student sent by government office or business
生す[nasu] to build up
異常発生[ijouhassei] plague
医学生[igakusei] medical student
医学生物学[igakuseibutsugaku] medical biology