1.If you were busy, I would leave you alone/ If you had been busy, I should have left you alone.
2.If my friend came to see me, I would be very glad/ If my friend had come to see me, I should have been very glad.
3.If mother bought a cake, we would have a very nice tea party/ If mother had bought a cake, we should have had a very nice tea party.
4.If we got a telegram from him, we wouldn't worry/If we had got a telegram from him, we shouldn't have worried.
5.If you didn't work hard, you would fail the exam/ If you hadn't worked hard, you should have failed the exam.
6.If I lived in Moscow, I would visit the Tretyakov Gallery every year/If I had lived in Moscow, I should have visited the Tretyakov Gallery every year.
7.If I got a ticket, I would go to the concert/If I had got a ticket, I should have gone to the concert.
8.If I lived near a wood, I would gather a lot of mushrooms/If I had lived near a wood, I should have gathered a lot of mushrooms.
9.If my father returned early, we would watch TV together/If my father had returned early, we should have watched TV together.
10.If she knew English, she would try to enter the university/ If she had known English, she should have tried to enter the university.