Объяснение:
1) If I had known it was your birthday, I would have prepare a present. 2) If you had called me earlier, I would have answered. 3) If Joe hadn't studied for his test, he would have failed it. 4) If I had seen you, I would have talked to you. 5) If Jane had left on time, she wouldn’t have been late. 6) If I hadn't overslept, I wouldn’t have been fresh. 7) If you had lent me the money, I could buy a new phone. 8) If Lan had caught the bus, he would have come in time.