1(1)231. …and leaves a person defenceless against infections and illnesses.(SB U7)Ⅱ…… 使人丧失对感染及疾病的抵抗力。leave vt. 让……处于某种状态4leave+ 宾语 +( 宾补 ) 过去分词过去分词现在分词不定式形容词介词短语 ①Please excuse me if I __________________( 对你的任何问题都没有回答 ) ．②Extremely angry, Mum walked away and __________________( 留下我一人坐在那儿 ). ③I __________________( 让门开着 )when I leave in case he comes back.④It should be better to __________________( 让他自个儿做 ). 6【答案】①(have) left any of your questions unanswered②left me sitting there all by myself③will leave the door open④leave him to do it himself72. Learning about first aid is the best way to make sure that we will not have to feel that we could have done more.(SB U8)Ⅱ学习急救是保证遇到此类事情不留遗憾的最佳途径。8could have done 的用法：（ 1 ）用于肯定句、否定句或疑问句中，对过去的动作进行可能性推测，也可用can have done 。 用 于 肯 定 句 中 相 当 于may/might have done 。例如：He can/could have left earlier. (can/could have left 相当于 may/might have left)他可能早离开了。9Surely she can/could not have arrived so early.他不可能到这么早。Can/Could he have left already?他可能已经离开了吗？10（ 2 ）用于肯定句中表示过去本来能够做而未做。例如：You could have caught the early train. ( 事实上没搭上 ) 你本应该搭上早班车。 ①__________________( 那会是舒适的旅行吗 ) since there were 6 people in the little car? ②I __________________( 本可以更加用功些的 ), but as a matter of fact, I have wasted too much time. 【答案】①Can that have been a comfortable journey②can have studied harder121. 由关系代词和关系副词引导的定语从句；2. 由介词＋关系代词引导的定语从句；3. 通过关系代词或关系副词来考查定语从句、 状语从句、名词性从句的区别。定语从句13 在复合句中，修饰某一名词或代词的从句叫定语从句。引导...
