A. is
B. was
C. were
D. be

A. explains
B. explained
C. explaining
D. explain

A. has
B. have
C. had
D. was

A. have
B. has
C. had
D. having

A. write
B. writing
C. is writing
D. was writing

A. have done
B. had done
C. did
D. done

A. watch
B. watches
C. watched
D. watching

A. meet
B. meets
C. met
D. meeting

A. go
B. goes
C. went
D. gone

A. finish
B. finished
C. have finished
D. had finished