1、Period 3 Grammar,Module 6 Unexplained Mysteries of the Natural World,情态动词,May have/might have,对过去的事实进行推测：结构：情态动词+have done / been+名词/形容词/介词短语 例句： 1. Mrs. Longmans must have been a pretty girl in her youth. 2. He couldnt have seen Anna yesterday. Shes gone abroad. 3. I think I must have left my glass
2、es in the library. 4. He might have overslept again. 5. Where can Tom have gone ?,情态动词表达虚拟语气：表达“本来”，“不然早就”。这是情态动词的一种虚拟语气用法。表示说话人所讲的与所发生的事实相反。表达了说话人的埋怨，后悔的语气。其结构是在一些情态动词后面加 have done 结构。根据要表达的意思，有如下结构： should have done / ought to have done：本应该 shouldnt have done / oughtnt to have done：本不该 could have
3、done：本来可以 neednt have done：本来没必要 would like to have done：本来很想 would rather not have done: 本来不愿意 could / might / have done: 不然早就,例句： 1. You shouldnt have laughed at his mistakes. 2. You could have told us earlier. 3. I ought to have bought that dictionary last week. 4. You ought not to have spent so
4、much time in reading novels. 5. We need not have been in a tearing hurry to catch the train. 6. They would like to have seen that film last film. 7. If he had given me his number, I could have telephoned him. 8. They might have been frozen to death but for the rescue in time.,Choose the best answer,
5、Something which happened in the pastperhaps Something which is impossible Something which may happen in the future,Complete the sentence：,The meteorite _(cause) a huge dust cloud. The dust cloud _(cut off) the sunlight Small animals _ (survive) by eating nuts and seeds. The dinosaurs _ (kill) by volcanic eruptions.,might have caused,may have cut off,may have survived,might have been killed,Work in pairs,Think of some more reasons why the dinosaurs might have disappeared. Use may have / might have,