CHỌN ĐÁP ÁN ĐÚNG NHẤT
12. By Christmas, I _______ for Mr. Smith for six years.
A. will have been working
B. will work
C. have been working
D. will be working
12. By Christmas, I _______ for Mr. Smith for six years.
A. will have been working
B. will work
C. have been working
D. will be working