Unit5ThepowerofnaturePeriod3课件（新人教版选修6）.ppt

Period 3　Grammar;v．-ing形式或v.-ing短语作状语往往修饰谓语动词表示动作，相当于相应的状语从句或并列句。 1．表示时间，作时间状语，相当于时间状语从句 Walking along the street，I met my old classmate.(＝While I was walking along the street，I met my old classmate.)我在街上走的时候碰到了老同学。;Turning on the light＝(When he turned on the light)，he was surprised to see his son lying on the floor. 他打开灯，惊讶地看见儿子躺在地上。 when/while＋动词的-ing形式强调其表示的动作和谓语动词动作同时发生。 Look out for cars when (you are) crossing the street.过街时注意车辆。 Don’t reach sideways while (you are) standing on a ladder.站在梯子上时，不要侧着身子伸手去拿东西。; 2．表示原因，作原因状语，相当于原因状语从句 Being too young(＝As he was too young)，he couldn’t join the army.因为太年幼，他不能参军。 Not knowing how to get there(＝As I did not know how to get there)，I had to ask the way. 因为不知道如何到那里，我只得问路。 ; 3．表示条件，作条件状语，相当于条件状语从句 Driving too fast(＝If you drive too fast)，you will damage the car.如果你开车太快，你会把车子弄坏的。 Having more time(＝If I have more time)，I will do the work much better. 如果我有更多时间，我会把工作做得更好。 ; 4．表示伴随状况或行为方式，这种用法没有相应的状语从句可以代替，但可以用并列复合句或两个简单句代替 Thousands of students stood there，watching. (＝Thousands of students stood there and watched.)成千上万的学生站在那儿观看着。 They came into the classroom，singing and laughing. (＝They sang and laughed，and came into the classroom.)他们又唱又笑地走进教室。; 5．表示结果，作结果状语，没有相应的状语从句代替 The child fell，striking his head against the door and cutting it.小孩摔了一跤，头在门上碰破了。 ;【温馨提示】 (1)当v.-ing形式作状语时，其逻辑主语就是句子的主语。如果v.-ing短语的逻辑主语和句子主语不一致，即为错句。 Standing on the top of the mountain，I found the houses below looked like tiny toys. 当我站在山顶上时，我觉得下面的房子就像小玩具一样。 (2)有时动词的-ing形式或动词的-ing短语有自???的逻辑主语，它们之间有逻辑上的主谓关系，称之为独立主格结构。 Class being over，the children could play football. 下课了，孩子们可以踢足球了。; (3)v.-ing为短语在句中作插入语，对全句作解释，此时不存在其逻辑主语必须和句子主语一致的问题。 Generally speaking，newspapers follow the American way. 一般地说，报纸采用美国英语的拼法。 Frankly speaking，I don’t enjoy the performance. 坦率地说，我并不喜欢这场演出。 ; (4)v.-ing形式的否定式 not doing/not having done Not knowing Tom’s telephone number，Mary was very anxious.不知道汤姆的电话号码，玛丽很着急。 Not having finished my shopping，I couldn’t go home. 还没买完东西，我不能回家。 ; (5)v.-ing的