1.一朝被蛇咬，十年怕草绳
2.一言既出，驷马难追
A word spoken is past recalling.
3.一见钟情
To fall in love at first sight.
4.一箭双雕/一举两得
Kill two birds with one stone.
5.一寸光阴一寸金
Time is money.
6.一失足成千古恨
The error committed on impulse may turn out to be the sorrow of a whole life.
7.一将功名万古枯
What millions died that Caesar might be great.
8.一年之计在于春，一日之计在于晨
Plan your year in spring and your day at dawn.
9.一人难称百人意
10.一气呵成
Never make two bites of a cherry.
11.九死一生
To have a hair-breadth escape.
12.九牛一毛
A drop in the bucket.
13.人生如梦
Life is but a dream.
14.人生自古谁无死
15.人不可貌相
Appearances are often deceptive./Never judge a book by its cover.
16.人山人海
A sea of faces：How many people are there in the stadium? Believe it or not, a sea of faces.
17.人云亦云
Echo others’ words.
18.人面兽心
A wolf in sheep’s clothing.
19.人言可畏
20.十年风水轮流转
Every dog has its day.
21.十全十美
22.十拿九稳
Win something in the bag.