WE HAVE KNOWN EACH OTHER FOR SOME YEARS, ...

16. - 3500 CAU TRAC NGHIEM ON TAP AV THCS
3500 CAU TRAC NGHIEM ON TAP AV THCS

16. We have known each other for some years, ... ?

a. have we

b. do we

c. haven't we

d. don't we

 c