—As we know, you won’t go back to the USA since you have established a research center here.But how long _____ in America?
—For almost 10 years.
A.did you study | B.have you studied |
C.were you studying | D.have you been studying |
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—As we know, you won’t go back to the USA since you have established a research center here.But how long _____ in America?
—For almost 10 years.
A.did you study | B.have you studied |
C.were you studying | D.have you been studying |