两虎相斗，
必有一伤 | liǎng hǔ xiāng dòu ,
bì yǒu yī shāng | When two tigers fight, one will get injured (idiom). If it comes to a fight, someone will get hurt. |
| 八一五 | bā yī wǔ | 15th August; refers to Japanese surrender in WWII on 15th August 1945 |
| 八分之一 | bā fēn zhī yī | one eighth |
| 八字没一撇 | bā zì méi yī piě | lit. there is not even the first stroke of the character 八; things have not even begun to take shape; no sign of success yet |
| 八字还没一撇 | bā zì hái méi yī piě | lit. there is not even the first stroke of the character 八; things have not even begun to take shape; no sign of success yet |
| 八字还没一撇儿 | bā zì hái méi yī piěr | lit. there is not even the first stroke of the character 八; things have not even begun to take shape; no sign of success yet |
| 六一儿童节 | liù yī Ér tóng Jié | Children's Day (June 1st), PRC national holiday for children under 14 |
| 六分之一 | liù fēn zhī yī | one sixth |
| 再一次 | zài yī cì | again |
冰冻三尺，
非一日之寒 | bīng dòng sān chǐ ,
fēi yī rì zhī hán | three feet of ice does not form in a single day (idiom); Rome wasn't built in a day |
| 冰山一角 | bīng shān yī jiǎo | tip of the iceberg |
| 凡事总有一个开头 | fán shì zǒng yǒu yī gè kāi tóu | Everything starts somewhere. |
| 别具一格 | bié jù yī gé | having a unique or distinctive style |
| 别树一帜 | bié shù yī zhì | lit. to fly one's banner on a solitary tree (idiom); fig. to act as a loner; to stand out; to develop one's own school; to have attitude of one's own |
| 别树一旗 | bié shù yī qí | lit. to fly one's banner on a solitary tree (idiom); fig. to act as a loner; to stand out; to develop one's own school; to have attitude of one's own |
| 前一天 | qián yī tiān | the day before (an event) |
| 刚一 | gāng yī | to be just about to; to have just started to |
| 划一不二 | huà yī bù èr | fixed; unalterable |
| 功亏一篑 | gōng kuī yī kuì | lit. to ruin the enterprise for the sake of one basketful; to fail through lack of a final effort; to spoil the ship for a ha'penny worth of tar (idiom) |
| 十・一 | shí · yī | first of October; PRC National day; same as 国庆 |
| 十一 | shí yī | eleven; 11 |
| 十一年 | shí yī nián | eleven years |
| 十一月份 | shí yī yuè fèn | November |
| 十一路 | shí yī lù | (colloquial) going on foot |
| 十二分之一 | shí èr fēn zhī yī | one twelfth |
| 十分之一 | shí fēn zhī yī | one tenth |
| 千虑一失 | qiān lǜ yī shī | reflect a thousand times and you can still make a mistake (idiom); to err is human |
| 千虑一得 | qiān lǜ yī dé | a thousand tries leads to one success (idiom, humble expr.); Even without any notable ability on my part, I may still get it right sometimes by good luck. |
千军易得，
一将难求 | qiān jūn yì dé ,
yī jiàng nán qiú | easy to raise an army of one thousand, but hard to find a good general (idiom) |
| 千金一掷 | qiān jīn yī zhì | lit. stake a thousand pieces of gold on one throw (idiom); to throw away money recklessly; extravagant |
| 千金一诺 | qiān jīn yī nuò | a promise worth one thousand in gold (idiom); a promise that must be kept |
| 千钧一发 | qiān jūn yī fā | a thousand pounds hangs by a thread (idiom); imminent peril; a matter of life or death |
| 南柯一梦 | Nán kē yī mèng | lit. a dream of Nanke; fig. dreams of grandeur |
| 又一次 | yòu yī cì | yet again; once again; once more |
| 反咬一口 | fǎn yǎo yī kǒu | to make a false counter-charge |
| 反正一样 | fǎn zhèng yī yàng | whether it's right or wrong doesn't make a lot of difference; six of one and half a dozen of the other; as broad as it is long |
| 取得一致 | qǔ dé yī zhì | to reach a consensus |
| 另一 | lìng yī | another; the other |
| 另一半 | lìng yī bàn | other half; fig. spouse; one's better half |
| 另一种 | lìng yī zhǒng | another kind |
只知其一，
不知其二 | zhǐ zhī qí yī ,
bù zhī qí èr | to know the first, but not know the second (idiom); only partial information |
吃一堑，
长一智 | chī yī qiàn ,
cháng yī zhì | Fall into the moat and you'll be wiser next time (idiom). One only learns from one's mistakes. |
| 各执一词 | gè zhí yī cí | each sticks to his own version (idiom); a dialogue of the deaf |
| 合一 | hé yī | to unite |
| 合众为一 | hé zhòng wéi yī | united as one; e pluribus unum |
同一个世界，
同一个梦想 | tóng yī gè shì jiè ,
tóng yī gè mèng xiǎng | One world - one dream, motto of 2008 Beijing Olympic games |
| 同声一哭 | tóng shēng yī kū | to share one’s feeling of grief with others (idiom) |
| 名噪一时 | míng zào yī shí | to achieve fame among one's contemporaries (idiom); temporary or local celebrity |
| 周一岳 | Zhōu Yī yuè | York Chow or Chow Yat-ngok (1947-), Hong Kong doctor and politician, Secretary for Health, Welfare and Food since 2004 |
| 周三径一 | zhōu sān jìng yī | circumference of a circle is proverbially three times its radius |
