病原体侵入机体，消弱机体防御机能，破坏机体内环境的相对稳定性，且在一定部位生长繁殖，引起不同程度的病理生理过程非谓语动词（非谓语动词（3））---过去分词过去分词1. 过去分词的语法作用： 过去分词一方面具有动词的性质，另一方面也相当于一个形容词或副词，在句中可以作表语、定语 状语和补足语 1)作表语如：Don’t touch the glass because it is broken. He is quite pleased with the design of the dress. 病原体侵入机体，消弱机体防御机能，破坏机体内环境的相对稳定性，且在一定部位生长繁殖，引起不同程度的病理生理过程•2)作定语：• 单个的过去分词作定语一般放在名词的前面如：•The excited people rushed into the building. •We need more qualified teachers. • 过去分词短语作定语通常放在被修饰的词后面，相当于一个定语从句如：•Is there anything planned for tomorrow? •The suggestion made by the foreign expert was adopted by the manager. 病原体侵入机体，消弱机体防御机能，破坏机体内环境的相对稳定性，且在一定部位生长繁殖，引起不同程度的病理生理过程•过去分词作定语也可用作非限制性定语，前后用逗号隔开。
如：•The books, written by Lu Xun, are popular with many Chinese people.• The meeting, attended by one thousand students, was a success. 病原体侵入机体，消弱机体防御机能，破坏机体内环境的相对稳定性，且在一定部位生长繁殖，引起不同程度的病理生理过程•3. 非谓语动词作定语时的区别•a meeting to be held tomorrow （表示将来的动作）• a meeting being held now（表示正在进行的动作）•a meeting held yesterday（表示完成的动作） 病原体侵入机体，消弱机体防御机能，破坏机体内环境的相对稳定性，且在一定部位生长繁殖，引起不同程度的病理生理过程•3) 过去分词作补足语：• 过去分词可以在see, hear, notice, watch, find, get, have, feel, make, leave, keep等词后与一名词或代词构成复合宾语，用作宾语补语如：•When will you go to the hospital and have your tooth examined? •When you are making a speech, you should speak louder to make yourself heard. 病原体侵入机体，消弱机体防御机能，破坏机体内环境的相对稳定性，且在一定部位生长繁殖，引起不同程度的病理生理过程•4) 过去分词做状语：• 过去分词和-ing分词作状语一样，也可以表示时间、原因、条件、让步、方式或伴随情况等。
•①表时间，相当于一个时间状语从句，有时过去分词前可加连词when或while来强调时间概念如：•Seen from the top of the hill, the city looked like a big garden. • Asked about his family, he made no answer. 病原体侵入机体，消弱机体防御机能，破坏机体内环境的相对稳定性，且在一定部位生长繁殖，引起不同程度的病理生理过程•②表原因，相当于一个原因状语从句如：•Deeply moved by the story, the excited people stopped quarrelling with each other.•Encouraged by the speech, the young people made up their minds to take up the struggle. •③表条件，相当于一个条件状语从句，有时过去分词前可用if等词如：•Given another chance, he will do better.• Compared with your brother, you should make greater efforts to study English.•If heated, water can be turned into steam. 病原体侵入机体，消弱机体防御机能，破坏机体内环境的相对稳定性，且在一定部位生长繁殖，引起不同程度的病理生理过程•④表让步，相当于一个though/although引导的让步状语从句。
如：•Exhausted by the running, they went on running after the robber. •尽管已经跑得筋疲力尽，他们还是继续追赶着那个强盗•Laughed at by many people, he continued his study•. ⑤表方式或伴随情况如：•The old man went into the room, supported by his wife.• Seated at the table, my father and I were talking about my job. 病原体侵入机体，消弱机体防御机能，破坏机体内环境的相对稳定性，且在一定部位生长繁殖，引起不同程度的病理生理过程•(注意）注意）. 过去分词作状语时，它的逻辑主语一般必须和句子的主语相一致如：•When asked why he came here, the boy kept silent.•Given more time ,we could do the work better.•如果过去分词的逻辑主语和句子主语不一致，必须使用过去分词的独立主格结构。
•独立主格中是使用-ing或是过去分词，则要根据它们的主语和其所表示的动作的关系而定，如：The bell ringing, we all stopped talking.• The test finished, we began our holiday. 。