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

一騎当千[ikkitousen] being a match for a thousand
一刻千金[ikkokusenkin] every moment is precious
一字千金[ichijisenkin] word of great value
一千[issen] 1,000
一望千里[ichibousenri] sweeping view of the eye

一瀉千里[isshasenri] one swift effort
引き千切る[hikichigiru] to tear off
何千[nanzen] many thousands
海千山千[umisenyamasen] sly old dog
幾千[ikusen] thousands

圧し石[oshiishi] stone weight
一石[isseki] one game (of go)
一石二鳥[issekinichou] killing two birds with one stone
英国石油[eikokusekiyu] British Petroleum
下石[shitaishi] nether millstone

化粧石鹸[keshousekken] toilet soap
化石[kaseki] fossil
化石学[kasekigaku] paleontology
化石層[kasekisou] fossil bed
化石燃料[kasekinenryou] fossil fuel

するが良い[surugaii] had better ...
どうしたら良い[doushitaraii] what's the best thing to do?
愛想の良い[aisonoii] affable
運良く[unyoku] luckily
温良[onryou] gentle

佳良[karyou] good
改良[kairyou] improvement
改良点[kairyouten] point(s) for improvement
格好の良い[kakkounoii] attractive
感度良好[kandoryoukou] loud and clear