1、第九讲名词性从句名词性从句是历年高考的重点和难点，也是热点。名词性从句相当于名词，可作主句的主语、宾语、表语和同位语。因此，名词性从句可分为主语从句、表语从句、宾语从句和同位语从句(见下表)。名词性从句连接词主语从句用 that,who,whether/if,what(the thingthat)等连接词引导。宾语从句用 that(可省略),if,whether(or not),what(the thing which)等连接词引导。表语从句用 that(一般不省略),whether,what(thething which)等连接词引导。同位语从句 用 that(常指代 news,though
2、t,idea 等词),whether 等连接词引导。结构常见句型It is名词主语从句It is a fact that.事实是/It is anhonor that.非常荣幸/It is commonknowledge that.是常识It is形容词主语从句 It is natural that.很自然/It isstrange that.奇怪的是一、主语从句主语从句是在复合句中充当主语的从句，通常放在主句谓语动词之前或由形式主语 it 代替，而本身放在句子末尾。1用 it 作形式主语的结构结构常见句型It不及物动词主语从句It seems that.似乎/It happened that
3、.碰巧/It appears that.似乎It is/has been过去分词主语从句It is reported that.据报道/It has beenproved that.已证实/It is said that.据说续表说明例句if 引导的主语从句不可位于复合句句首Its unknown whether/if he will come.(正)Whether he will come or not is unknown.(正)If he will come or not is unknown.(误)It is said/reported.结构中的主语从句不可提前It is said t
4、hat Jiang will visit our school.(正)Jiang will visit our school next week is said.(误)It happens/occurs.结构中的主语从句不可提前It occurred to him that he failed in the examination.(正)That he failed in the examination occurred to him.(误)It doesnt matter how/whether.结构中的主语从句不可提前It doesnt matter whether he is right
5、 or not.(正)Whether he is right or not doesnt matter.(误)含主语从句的复合句是疑问句时，主语从句不可提前Is it likely that it will rain in the evening?(正)Is that it will rain in the evening likely?(误)2.主语从句不可位于句首的五种情况说明例句作动词的宾语由 that 引导的宾语从句(that通常可以省略)I heard(that)he joined the army.我听说他参军了。由 what,whether/if,when,where 等引导的宾
6、语从句She did not know what had happened.她不知道发生了什么。动词间接宾语宾语从句She told me that she would accept myinvitation.她告诉我她将接受我的邀请。二、宾语从句宾语从句是在复合句中作宾语的名词性从句，通常放在主句谓语动词(及物动词)或介词之后。说明例句作介词的宾语Our success depends upon how well wecan cooperate with one ano-ther.我们的成功取决于我们互相合作得有多好。作形容词的宾语I am afraid(that)Ive made a mi
7、stake.恐怕我犯了个错。it 作形式宾语We heard it that she would get marriednext month.我们听说她下个月打算结婚。否定前移(若主句主语为第一人称，且谓语动词为 think,consider,suppose,believe,expect,fancy,guess,imagine 等，其后的宾语从句若含有否定意义，一般要把否定词转移到主句谓语上，从句谓语用肯定式)I dont think this dress fits you well.我认为这件衣服不适合你穿。续表三、表语从句表语从句是在复合句中作表语的名词性从句，放在系动词之后，一般结构是“
8、主语连系动词表语从句”。可以接表语从句的连系动词有 be,look,remain,seem 等。引导表语从句的引导词 that 一般不省略。另外，常用的含有表语从句的结构还有“The reason why.is that.”和“It is because.”等。如：The reason why he is late for school is that he missed the earlybus.他上学迟到的原因是他错过了早班车。说明例句同位语从句的功能(一般由 that 引导，that 不作句子成分，但也不可省略)对于名词进一步解释The kings decision that the p
9、risonerwould be set free surprised all thepeople.国王做出释放那个罪犯的决定让所有人都很吃惊。说明名词的具体内容The order that all the soldiers shouldstay still was given by the gene-ral.所有的士兵都应该保持不动，这个命令是将军下的。同位语从句在句子中的位置有时可以不紧跟在它所说明的名词后面，被别的词隔开He got the news from Mary that thesports meeting was put off.他从玛莉那里得到消息运动会被推迟了。四、同位语从句
10、同位语从句是在复合句中作同位语的名词性从句。五、whether,if(是否)引导名词性从句的区别1句首引导主语从句或出现 or not 时，只能用 whether。2if 不能引导表语从句。3if 不能引导介词后的宾语从句和同位语从句。4宾语从句是否定句只能用 if。5discuss 后的宾语从句只能用 whether 引导。注意：doubt 作“怀疑”解，后接宾语从句时，如主句是 肯定句，宾语从句用 whether 或 if 引导；如主句是否定句或疑 问句，宾语从句只能用 that 引导。如：I doubt whether/if he is fit for the job.我怀疑他是否胜任这份工作。I dont doubt that he can do it very well.他能把它做好，我不怀疑。
