我学了三年英语

特殊疑问句是以特殊疑问词开头，对句中某一成分提问的句子。常用的疑问词有（特殊疑问词）：what 、who 、whose 、which 、when 、where 、how 、why等。回答特殊疑问句时，不能用yes / no，即问什么答什么，尤其是简略回答。所以可以改为提问：你学英语多长时间了？用英语表达是How long have you learned English? 问多长时间要用how long 而学英语这件事是仍在进行的，所以得用现在完成时。

我学英语已经三年了。I have learned English for three years. 特殊疑问句是How long have you learned English?

I have been learning English for three years.个人觉得用现在完成进行时好一点表示一直在学现在还在学。

I have been learning English for three years.

It has been 3 years since I learned English.