Dear teacher,For I am badly ill now, I would like to ask for a 2-month off. I promise that I'll try my best to learn English in the future.Sincerely,your name.不是现在向老师请假，是已经请好了假，已经过了两个月，回到学校，向老师说明情况。。。。更不是写信。。。这样啊，那就是：I was sick two months ago, so I asked for a two-month off. I promise that I'll try my best to study English from now on.翻译：因为我两个月前生病了，所以请了两个月的假。我允诺从现在开始会一直好好学习英文的。