英语练习：Happpy birthday，Alice ！So you have _____ tweny-one today.

C. turned
这里turn means to reach a certain age or time
达到某一年龄或时间
e.g. He's just turned 40. It's just turned 3 o'clock.

选C，英语习惯，就好象翻日历一样从20岁“翻（turn）”到了21岁。