20-90用英语分别是：twenty thirty forty fifty sixty seventy eighty ninety。
twenty 英[ˈtwenti] 美[ˈtwɛnti, ˈtwʌn-]
n. 二十，二十个; 二十多岁; 二十年代; 许多，大量;
num. 二十;
adj. 二十的;
[例句]They're both in their twenties and both married with children of their own.
他们俩都二十几岁，都已经结婚生子了。
thirty 英[ˈθɜ:ti] 美[ˈθɜ:rti]
n. 三十; 三十个; 三十年代; 三十的记号;
adj. 三十的，三十个的;
num. 三十; 三十个;
[例句]Mozart clearly enjoyed good health throughout his twenties and early thirties.
显然，
莫扎特在二十几岁到三十刚出头时，身体非常好。
forty 英[ˈfɔ:ti] 美[ˈfɔ:rti]
n. 四十; 四十几;
adj. 四十的;
[例句]He was a big man in his forties, smartly dressed in a suit and tie.
他是一个四十多岁的高大男子，穿西装打领带，看上去很精神。
seventy 英[ˈsevnti] 美[ˈsɛvənti]
n. 七十; 从七十到七十九的数目、年数或温度;
[例句]Seventy people were killed.