½ = one half；1/3 = one third；
¼ = one quarter；
1/5 = one fifth；
1/ 6 = one sixth；
3/5 = three fifths；
1.5% = one point five percent
0.3% = nought / zero point three percen
t2:1 = two to one （英式英语里的数字0一般用nought美式英语里则惯用zero）
