Unit 4 Cartoons and comic strips第 3 课时——语法课后拓展课时精讲栏目导航课时过关单元语法讲解： （一）含有情态动词的被动语态（The passive voice with modal verbs） 形式 结构 例句 肯定形式 动作承受者+情态动词 +be+ 动 词 的 过 去分词 A tree should be planted here. The bag must be checked now. 否定形式 动作承受者+情态动词+not+be+动词的过去分词 A tree should not be planted here. The bag must not be checked now. 一般疑问句 情态动词+动作承受者 +be+ 动 词 的 过 去分词 Should a tree be planted here? Must the bag be checked now? 肯定回答 Yes, 动作承受者+情态动词 —Should the house be cleaned today? —Yes, it should. 否定回答 No, 动作承受者+情态动词+not —Must the speech be given tomorrow? —No, it needn’t. 按照要求完成句子。 1．This pair of trousers should be washed again.（改为否定句） 2．The water should be cleaned before you drink it．（改为一般疑问句） This pair of trousers should not be washed again. Should the water be cleaned before we drink it? 3．Must a test paper be checked before we hand it in?（作肯定回答） 4．Can those trees be cut down right now?（作否定回答） Yes, it must. No, they can’t. 5．You must take those books back to the library.（改为被动语态） 6．Parents can take their children to the cinema on Children’s Day.（改为被动语态） Those books must be taken back to the library. Children can be taken to the cinema by their parents on Children’s Day. （二）现在完成时的被动语态（The passive voice in the present perfect tense） 形式 结构 例句 肯定形式 动 作 承 受 者+has/have+been+动词的过去分词 The girl has been sent back home. Two dolls have been bought for my sister. 否定形式 动 作 承 受 者+has/have+not+been +动词的过去分词 The girl hasn’t been sent back home. Two dolls haven’t been bought for my siste...
