When the boss into the office, his secretary, and the accountant on the phones. A. was walking / has been typing / has been talking B. had walked / was typing / had talked C. walked / was
When the boss .... into the office, his secretary ...., and the accountant .... on the phones.
A. was walking / has been typing / has been talking
B. had walked / was typing / had talked
C. walked / was typing / was talking
D. had been walking / had typed / talked