a) When he called me, I (make) {input: had been working} on a presentation for over two hours – and I still had a lot to do.
b) They looked angry because they (wait) {input: had been waiting} for more than an hour.
c) We (negotiate) {input: had been negotiating} for the whole week before they finally signed the agreement.
d) He (deal) {input: had been dealing} in e-commerce for K&F Ltd for six years before he joined us.
e) Ian (work) {input: had been working} at the factory for a long time before he became a manager.
f) They (manufacture) {input: had been manufacturing} pulp-and-paper products for many years before deciding to enter the High Technology market.
g) We (train) {input: had been training} the staff for several weeks before we had a winning team.
h) She (stay) {input: had been staying} in the same hotel for a week when I suddenly saw her.