if条件句讲解及练习从句主句与现在事实相反过去式（be 用were）would/should/could/might+ do与过去事实相反过去完成式would/should/could/might + have done与将来事实相反should (were to) +动词原形would/should/could/might + doIf I were you, I would not let out the secret. 如果我是你的话，我不会泄露这个秘密的。If I knew his new address, I would tell you.如果我知道他的新地址，我会告诉你的。If he studied harder, he would pass the exam.如果他学习再努力点的话，他会通过考试的。If we had made fuller preparation, we should have won the game. 如果我们做了更充分的准备的话，我们肯定就赢了这场比赛
