33Unit4章节幻灯片.pptVIP

主语从句（Noun Clauses as the Subject） 定义： 用作主语的从句叫主语从句，它是名词性从句之一。引导主语从句的连接词有：连词that, whether；连接代词who, what和which；连接副词when, where, how和why。 用法： 1) 由what等代词引起的主语从句： What the teacher said today was quite right.? 老师今天说的话是十分正确的。 2) 由连词that引起的主语从句： That they are badly in need of help is quite clear. 他们急需帮助，这是十分明显的。 但是这类句子在大多数情况下会放到整个句子的后部去，而用代词it作形式主语。 3) 由连接代词或连接副词以及whether引起的主语从句。 Whether they will sell the house is not yet decided. 他们是否卖掉这所房子还没有决定。 4) whatever, whoever也可引导主语从句。 Whatever was said here must be kept secret. 这里说的话都应当必威体育官网网址。 Whoever makes mistakes must correct them. 凡犯了错误的人都必须改正。 注意: 上述例句中的主语从句都是放在句首, 但有时为了使句子结构平衡, 避免 “头重脚轻”, 常用 it 作形式主语, 而把从句放在后面。 例如: 　　It is a pity that she has made such a mistake. 她犯了这样一个错误, 真是遗憾。 这样就构成了下面一些常用句型: 1) It is + adj. / n. +从句 　 It is a pity/shame that... 遗憾的是…… 　 It is possible that... 很可能…… 　 It is unlikely that... 不可能…… 2) It +不及物动词+从句 　 It seems/appears that... 似乎…… 　 It happened that... 碰巧…… 　3) It + be +过去分词+从句 　　It is said that... 据说…… 　　It is known to all that... 众所周知…… 　　It is reported that... 据报道…… 　　It is believed that... 据信……;人们相信…… 　　It is suggested that... 有人建议…… It must be pointed out that... 必须指出…… It has been proved that... 已证明……. 如: It is believed that at least a score of buildings were damaged or destroyed. 据信, 至少有二十座楼房遭到破坏或彻底毁掉。 5) . 用于It is important / natural / necessary / impossible that...句型中, 主语从句应使用虚拟语气, 谓语动词用\“should + 动词原形\”的形式, should有时有感情色彩。 1. _____ you don’t like him is none of my business. 2. _____ he said at the meeting astonished everybody present. 3. ________ the 2000 Olympic Games will be held in Beijing is not known yet. 4. ________ we’ll go camping tomorrow depends on the weather. 5. ________ leaves the room last ought to turn off the lights. That What Whether Whether Whoever