推荐回答(4个)
1、判别方法不同
主语从句中 It is / was 后通常有名词或形容词作表语,而强调句型中 It is/ was 后是对主语、宾语或状语的强调成分。其判别方法是去掉强调句式结构或经过语序调整后,原句仍成立。这也是强调句型与主语从句及其它句式的重要区别之一。
2、侧重点不同
It is difficult to answer the question。It在句子中做形式主语,其真实主语是answer the question,即原句为Answer the question is difficult,用It做主语是为了保持句子平衡。
It was here that I came,这是强调句。原句应为I came here.用强调句是为了强调here这个地方。
3、作用和潜在逻辑不同
强调句型是用来强调句子中的某种成分的,我们经常见到的是强调主语、宾语或者状语,而没有见到过强调谓语的情况,如果强调的是谓语,去掉后剩下的怎么能成一个完整的句子。相对来说,形式主语的作用则是,因为原先句子的主语过长,为了避免头重脚轻的现象,所以发明了这个“形式主语”。

也就是说it不是真正的主语,而只是形式上的,真正的主语是其“指代”的that或to do,你可以理解为强调句型的这种结构是加在一个完整的句子上的,表明的是对be之后的部分的强调,同时,be之后的部分与that之后的部分是有相互作用关系的;最后,强调句型中的be根本不说明it的任何性质。
4、性质不同
形式主语是动词不定式的一种,它也是逻辑主语, 可以把它归类到逻辑主语的第一种(不定式的逻辑主语) 用作宾语的不定式,用作目的状语,用作结果状语的不定式都是属于不定式的大概念里面的。
强调句,是基本语法 ,是一种修辞,是人们为了表达自己的意愿或情感而使用的一种形式。英语常用的强调结构是"It is (was)+被强调部分(主语、宾语或状语)+who (that)..."。
通过各种方式对句子中的某个部分进行强调,从而起到修辞的作用。一般说来,被强调部分指人时,用who。指事物时用that,但that也可以指人。在美国英语中指事物时常用which来代替that。
参考资料:
百度百科-形式主语
百度百科-强调句
1、结构不一样
it引导的主语从句,形式主语就是it,真正的主语在句子的后面,通常是to do的不定式短语。而强调句的结构 it is/was+被强调部分+that/who+句子其余部分,结构词it is/was和that/who都是没有实际意思的,只是构成句子结构的词而已。
2、句式不一样
形式主语真正的主语在句子的后面,通常是to do的不定式短语。强调句只能强调名词和代词,也就是主语和宾语,不能强调其他句子成分。
3、区别方法不一样
判断强调句的最好办法是:把It is /was 后的部分放到 that/who 之后的句子里,如果能组成完整的句子,就是强调句,否则就不是。例如:
It is the boy who I care for. 把the boy 放到后面,是 I care for the boy. 句子完整,所以原句是强调句。
It is fun that we spend the holiday here. 无论怎样,fun 都不能放到后面组成完整的句子,所以原句不是强调句。

扩展资料:
主语从句中it做形式主语的常见句型:
1、It + be + 形容词+主语从句,如:It is uncertain whether he can come to Jenny’s birthday party or not.
2、 It + be + 名词词组 + 主语从句,这类名词有:a fact, a pity, a shame, an honour,a question等,如:It’s a pity that you missed the exciting football match.
3、It + be + 过去分词+ 主语从句,这类过去分词有:announced, believed, expected, hoped, decided, reported, said, shown等,
如:It is reported that 16 people were killed in the earthquake.
it做形式主语,后面内容做句子真正主语,除了由主语从句充当之外,还可以由不定时,不定时短语,动名词以及动名词短语充当,例如:It is very useful to learn English so well.
形式主语和强调句的区别
判断强调句的最好办法是:把It is /was 后的部分放到 that/who 之后的句子里,如果能组成完整的句子,就是强调句,否则就不是。例如:
1. It is the boy who I care for.
把the boy 放到后面,是 I care for the boy. 句子完整,所以原句是强调句。
2. It is fun that we spend the holiday here.
无论怎样,fun 都不能放到后面组成完整的句子,所以原句不是强调句。
判断强调句的最好办法是:把It is /was 后的部分放到 that/who 之后的句子里,如果能组成完整的句子,就是强调句,否则就不是.例如:
1.It is the boy who I care for.
把the boy 放到后面,是 I care for the boy.句子完整,所以原句是强调句.
2.It is fun that we spend the holiday here.
无论怎样,fun 都不能放到后面组成完整的句子,所以原句不是强调句.
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