3)连接副词when，where， how， why等。
Why they suddenly disappeared still remains a mystery. When they will leave is not decided. Where she is from is unknown. How we will paint the house has not been decided.
主语从句的规律：
例3. If the meeting will be put off has not been decided yet.
正： Whether the meeting will be put off has not been decided yet.
规律三、whether 可以引导主语从句， 放在句首，但if不能
natural. 正：It is natural (that) they should like
each other.
2)如果主语从句放在句首，不能用if引 导，但是如果用it 做形式主语，而把主 语从句放在句末时，也可以用if引导.
或把if 改为whether
误：If Mary really heard him is really doubtful. 正：It was doubtful if Mary really heard him.
*__It_i_s_a__f_a_c_t _th_a_t_(这是事实)he cheated in the exam.
2) It is + adj. +从句 It’s certain that… 肯定… It is possible that... 很可能…… It is unlikely that... 不可能…… It is obvious that… 很明显… It is necessary \important \natural\... that… +(should) +do…
规律五、含主语从句的主句谓语动词多用 单数第三人称形式。
主语从句的规律：
1. What he needs is that book.
2. What he needs are some books.
规律六、what 引导的主语从句，可根据 表语决定主句动词的单复数形式。
规律七、主语从句为了避免头重脚轻现 象，用 it 做形式主语，而 把从 句放在后面。
decided. we shall 2.You have made a mistake is a fact.
That you have 3. If the policeman will come is not certain.
Whether
4. That is certain that we can win. It
注意:
1）主语从句在句首时，必须由连接词引 导，不能省略这些连接词；但是如果用it 做形式主语，而把主语从句放在句末时， 从属连词that可以省略。
误：They should like each other is natural. 正：That they should like each other is
1）从属连词：that， whether等. that 引导主语从句只起引导作用，本身无实 际意义，whether 有含义，但 与that一样在 主语从句中不充当任何成分，不能省略。
That he will win is certain.他肯定会赢。 Whether he’ll come here isn’t clear. 他 是否会来这里还不清楚。
什么叫名词性从句？
• 在句子中起名词作用的句子叫名词从句 (Noun Clauses）
• 名词从句的功能相当于名词词组, 它在 复合句中能担任主语、宾语、表语、同 位语等
• 因此根据它在句中不同的语法功能，名 词从句又可分别称为主语从句、宾语从 句、表语从句和同位语从句
名词性从句 noun clause
It must be admitted that…必须承认……
It cannot be denied that… 不可否认……
It must be pointed out that…需指出的是……
*_I_t_i_s__re_p__o_r_te__d_t_h_a_t__(据报道)20 people were
主语从句 subject clause
宾语从句 object clause
表语从句 predicative clause
同位语从句 appositive clause
Grammar
Grammar
主语从句：
做主语用的名词性从句，因其在复合句中做主语， 又称主语从句，引导主语从句的有连词that ， whether， 连接代词who ，what ，which， 连 接副词when，where， how， why等。
That the earth turns around the sn to all that the earth turns around the sun.
找出错误，并给出理由： 1.Where shall we spend the holiday isn’t
以和ever构成合成词，和what一样引导从句，ever起到 强调作用。此类主语从句不能用形式主语it引导，它们在 句子中担任成分，不能省略，语序为陈述语序)
What many scientists believe is that the earth is round …
Who will take part in the meeting has not been decided.
Conclusion: 主语从句作主语时，谓语动词一般用单数形式。
主语从句的规律：
找出下列句子中的错误，并总结规律
例1.When will he come is not known. 正：When he will come is not known.
规律一、主语从句一律用陈述语序， 即主语在前，谓语在后。
Whoever breaks the law will be punished.
Which student will win is uncertain. Whatever was said here must be kept secret.
这里说的话都应当保密。 Whoever makes mistakes must correct them.
4) 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 + (should）do... 建议……
It is a pity/shame that... 遗憾的是…… It is a surprise that…令人惊奇的是… It is a fact that… …是事实 It is common knowledge that… …是常识
*__It_i_s_a__p_i_ty__th_a_t__(很遗憾)we lost the match.
正: Whether Mary really heard him is really
doubtful.
Complete the sentences using what, whether, where,
when， who, why, how or that.
1.(__W__h_atis needed for success) is your hard work. 2W.(h_e_n_/_H_o_wthey will arrive )has been told to the teacher. 3.(W__h_e_r_e/wwheewthilelrgo tomorrow )hasn’t been decided yet. 4.(__W__h_o_ can join in the sport meet) is decided by the teach 5.(_W__h_e_th__er_ it will rain or not) is not clear.
5. It is ordered we should leave at
once.
that
6. Where he comes from are a
碰巧……
It occurred to me that…我突然想起…
*_I_t_h_a_p_p_e_n_e_d__t_h_a_t_(刚好)I came into the office at that time.
*_I_t _o_c_c_u_r_re_d__t_o_m__e_t_h_a_t_(我突然想起)I forget to sent the letter.
注意: 由that 引导的主语从句有时为了使句
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:
1. That he will refuse this piece of advice is impossible. __I_t _is__im__p_o_s_s_i_b_le__th_a_t_h__e_w_i_ll_r_e_f_u_s_e_t_h_i_s_p_i_e_c_e __o_f_a_d_v_i_c_e_._____________________________
主语从句的规律：
例4. That whether he will help others is a fact.
正：That he will help others is a fact.