1.
а. If I were not too busy, I should go to the concert.
б. If I hadn't been too busy, I should have gone to the
concert.
2.
а. They would all be surprised if I made such a
mistake.
б. They would all have been very surprised if I had
made such a mistake.
3.
а. If he didn't come on time, should we have to wait
for him?
б. If he hadn't come on time, should we have had to
wait for him?
4.
а. If no one came to help, we should be obliged to do
the work ourselves.
б. If no one had come to help, we should have been obliged
to do the work ourselves.
5.
а. If you put on your glasses, you would see better.
б. If you had put on your glasses, you would have seen
better.
6.
а. What should we do if they were late?
б. What should we have done if they had been late?
7.
а. Would you be very angry if we didn't come?
б. Would you have been very angry if we hadn't come?
8.
а. Would he be very displeased if I didn't ring him up?
б. Would he have been very displeased if I hadn't rung
him up?