—How long have you learnt English?.A. Since B. In C. 4 years ago D. since 4 ye

问题补充：

—How long have you learnt English?

--- .

A. Since

B. In

C. 4 years ago

D. since 4 years

答案：

(答案→)A. Since

B. In

C. 4 years ago

D. since 4 years

解析：Since 自从以来；In 在；4 years ago 四年前；since 4 years结构有误，since后不能接一段时间。根据上文，你学英语多久了？可知选A。