She ________ for 12 years by the time she graduates from the Foreign Language Institute．
A.has studied English
B.has been studying English
C.had studied English
D.will have been studying English
网友回答
D解析本题考查将来完成进行时。“by+将来的时间”是将来完成时的标志，而“学习”这个动作是一直进行的，因此选D项。