英文推荐信中的题目in what capacity have you known the applicant?

题目

英文推荐信中的题目in what capacity have you known the applicant?
how long have you known the applicant?这个第一题是不是要写一句话最好 I have knwon the applicant for three years.这样写可以吗?
in what capacity have you known the applicant?这是问以什么身份和立场认识的申请者,这句话用英文怎么回答,

答案

I have known the applicant for three years. 

I was (或 am) [根据这个老师是否现在还是你的老师] the applicant's highschool History and Languages teacher.