1. If you are busy, I'll leave you alone.
If you were busy, I would leave you alone.
If you had been busy, I would have left you alone.
2. If my friend comes to see me, I'll be very glad.
If my friend came to see me, I would be very glad.
If my friend had come to see me, I would've been very glad.
3. If mother buys a cake, we will have a very nice tea party.
If mother bought a cake, we would have a very nice tea party.
If mother had bought a cake, we would have had a very nice tea party.
4. If we receive a telegram from him, we won't worry.
If we received a telegram from him, we wouldn't worry.
If we had received a telegram from him, we wouldn't have worried.
5. If you don't work systematically, you will fail the exam.
If you didn't work systematically, you would fail the exam.
If you hadn't worked systematically, you would have failed the exam.
6. If I live in Moscow, I'll visit the Tretyakov Art Gallery every year.
If I lived in Moscow, I would visit the Tretyakov Art Gallery every year.
If I had lived in Moscow, I would have visited the Tretyakov Art Gallery every year.
7. If I get a ticket, I'll go to the Philharmonic.
If I got a ticket, I would go to the Philharmonic.
If I had got a ticket, I would have gone to the Philharmonic.
8. If I live near a wood, I will gather a lot of mushrooms.
If I lived near a wood, I would gather a lot of mushrooms.
If I had lived near a wood, I would have gathered a lot of mushrooms.
9. If my father returns early, we will watch TV together.
If my father returned early, we would watch TV together.
If my father had returned early, we would have watched TV together.
10. If she knows English, she will try to enter the university.
If she knew English, she would try to enter the university.
If she had known English, she would have tried to enter the university.
2. Нет
3. Что - бы
4 . Нет