Переделай предложения, образуя conditional 2 и conditional 3 1) if i am not too busy, i shall go to the concert. 2) if i come home late, i shall be very sorry. 3) if he receives my letter, he will be very happy. 4) if she doesn't come in time, we shall not have to wait for her. 5) what shall we do if they are late?

1 If I weren't too busy, I should go to the concert.
If I hadn't been too busy, I should have gone to the concert.
2 If I came home late, I should be very sorry.
If I had come late, I should have been very sorry.
3 If he received my letter, he would be very happy.
If he had received my letter, he would have been very happy.
4 If she didn't come in time, we shouldn't have to wait for her.
If she hadn't come in time, we shouldn't have had to wait for her.
5 What should we do if they were late?
What should have we done if they had been late?