I remember my sister has studied English for 5 years in China( ) she went to the USA.A after B beforeC when

I remember my sister has studied English for 5 years in China( ) she went to the USA.A after B beforeC when
I remember my sister has studied English for 5 years in China( ) she went to the USA.
A after
B before
C when

I remember my sister has studied English for 5 years in China( ) she went to the USA.A after B beforeC when
选B
我记得,在我妹妹去美国之前,她已经在中国学了五年英语.
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b
现在完成时 has stuidied
我记得，在我妹妹去美国之前，她已经在中国学了五年英语

选择C，根据句意可排除A；另外看到从句用过去时，主句用现在时，说明主句发生的时间需在从句之后或者当时，因为如果在之前的话，时态改用过去完成时。（个人鄙见！望修改！）