1. c) had been working
2. a) invested b) have invested c) invest - любой из 3 может подойти
3. b) had already shipped
4. c) hadn't arrived
5. a) have bought
6. a) have increased b) have been increasing - оба применимы
7. a) had gone b) has gone - оба можно использовать
8. c) had been working
1. b) has been paid
2. b) will be signed
3. a) was left
4. a) is sold
5. a) was being signed