WHEN WE CAME, THE STADIUM ...A. WAS BEING FILLEDB. HAS FILLEDC. FI...

11. - 3500 CAU TRAC NGHIEM ON TAP AV THCS
3500 CAU TRAC NGHIEM ON TAP AV THCS

11. When we came, the stadium ...

a. was being filled

b. has filled

c. filled

d. is being filled

-> a