obvious明显的 natural自然的
It's certain that he will succeed. 他肯定会成功的。 [名师点津]
strange奇怪的
在It is necessary/important/strange/natural＋that从句结构中，从句常用“should＋动词原形”形式，其中should可省略。
It is necessary and important that you(should)master a foreign language so as to meet the need of a job.
为了工作的需要，你掌握一门外语是很有必要并且是很重要的。 It is strange that you(should)trust Jane. 很奇怪你竟然相信简。
②It＋系动词＋名词(短语)＋that从句 常用于这种句型的名词(短语)有： a pity遗憾 good news好消息 an honour荣耀 no wonder难怪
a shame遗憾，耻辱 a fact事实 a wonder奇迹 duty责任
It is a pity that you didn't attend the lecture yesterday. 你昨天没参加讲座真是遗憾。
It is our duty that we should help the people in need. 帮助那些处在困境中的人是我们的责任。 ③It＋be＋动词的-ed形式＋that从句 常见的动词的-ed形式有： said据说 heard有人听说 hoped有人希望 pointed out有人指出 suggested有人建议 ordered根据命令 thought有人认为 well known很著名
It's said that Tu Youyou has won the Nobel Prize in Physiology or Medicine. 据说屠呦呦获得了诺贝尔生理学或医学奖。
told有人告诉 reported据报道 turned out结果 decided作出决定 advised有人建议 remembered有人记得 considered据认为
[名师点津]
在“It＋be＋suggested/advised/ordered/requested/insisted/required/ decided＋that从句”的结构中，that从句中的谓语动词应用“should＋动词原形”，should也可省略。
It was decided that they(should)start the project the next month. 他们下个月开始这项工程已经定下来了。
It is suggested that you(should)spend more time in studying English. 你应该花更多的时间学习英语。 ④It＋特殊动词＋that从句
常见的此类动词有seem，happen，matter，occur等。 It really matters that you haven't turned up. 你没来，这的确很重要。
2．由whether，if引导的主语从句
当主语从句位于句首时，只能用whether，不用if引导主语从句；当it作形式主语，主语从句放在句末时，用whether或if均可。
Whether the meeting will be held is still a problem. 是否举行会议仍然是一个问题。
It is doubtful whether/if he will come here. 他是否来这里是令人怀疑的。 3．特殊疑问词引导的主语从句 What they need is a good text-book. 他们需要的是一本好的教科书。
Whichever he likes will be given to him. 无论他喜欢哪一个都可以给他。
Whatever/What changes we make in our plans will be announced later. 在我们的计划里不管有什么改变，以后都要公布。 [即时演练1] 单句语法填空
①It is often the case that anything is possible for those who hang on to hope. ②How we understand things has a lot to do with what we feel.
③Where Li Bai，a great Chinese poet, was born is known to the public, but some won't accept it.
(二)宾语从句
在句中起宾语作用的从句称为宾语从句。宾语从句可分为三类：动词(短语)的宾语从句、介词的宾语从句和形容词的宾语从句。
1．动词(短语)的宾语从句
大多数动词(如hope，tell，say，know，think，consider，imagine，hear，expect，suppose，guess等)后可以接宾语从句。
We all expect that they will win，for members of their team are stronger. 我们都预料他们会赢，因为他们的队员更强壮。 [名师点津]
动词find，feel，think，consider，make，believe等后有宾语补足语时，则需要it作形式宾语而将that宾语从句后置。
I think it necessary that we take plenty of boiled water every day. 我认为每天多喝开水是有必要的。 2．介词的宾语从句
(1)一般情况下介词后只能用wh-类连接词引导宾语从句。
We are talking about whether we admit students into our club. 我们正在讨论是否应该让学生加入我们的俱乐部。
We could see the temple quite clearly from where we lived. 我们能从我们住的地方清楚地看到寺庙。
(2)that引导的从句作介词宾语是很少有的，只有在except，in，but等介词后偶尔可能用到。
Your composition is quite good except that the organization is a bit loose. 除了结构有点松散以外，你的作文相当不错。
He differed from his colleagues in that he devoted his spare time to reading. 他和他的同事们不同的地方在于他把业余时间用在阅读上。 3．形容词的宾语从句
类似于sure，certain，glad，sorry，amazed，surprised，proud，pleased，shocked，disappointed等表心理状态的形容词后，可以跟that从句或wh-从句作宾语。
I'm sure/certain that he'll succeed. 我确信他会成功。
She was not aware how dangerous it was. 她没意识到当时有多危险。 4．注意事项
(1)宾语从句的语序和时态。宾语从句一律要用陈述语序。若主句是祈使句或主句用的是一般现在时/一般将来时，从句可根据需要选用合适的时态；若主句用的是过去的某种时态，从句一般用过去的某种时态；若从句表达的是客观事实、真理、自然现象等，从句通常用一般现在时。
The teacher told us that Tom had left us for America. 老师告诉我们汤姆离开我们去美国了。
The teacher said that the sun rises in the east and sets in the west. 老师说太阳东升西落。
(2)否定转移：当think，believe，suppose，imagine等动词的主语是第一人称，谓语为没有副词修饰的一般现在时，它们的否定实际上是对宾语从句的否定。变反意疑问句时简略问句的主语和谓语应与宾语从句的主语和谓语分别保持一致。
I don't think he can remember the 100 words within two hours，can he? 我想他不能在两小时内记住这100个单词，是吗？ (3)引导词that不能省略的情况：
①当主句的谓语动词与宾语从句之间有插入语时，引导词that通常不省略。 ②当一个动词带有两个或两个以上that引导的宾语从句时，第一个that可以省略，第二个及第二个以后的that不可以省略。
I believe (that) you have done your best and that things will improve. 我相信你已经尽力了，而且一切都会好起来的。 (4)用whether而不用if引导宾语从句的情况： ①与or not连用时
I want to know whether it's good news or not. 我想知道是否是好消息。 ②从句位于介词之后时
I worry about whether he can survive the crisis of his illness. 他生病了，我担心他能否度过危险期。 [即时演练2] 单句语法填空
①They want to make it clear to the public that they do an important job. ②It depends on whether it's going to rain.
③Pick yourself up. Courage is doing what you're afraid to do. (三)表语从句
在句中作表语的从句称为表语从句。能引导宾语从句的连接词(if除外)皆可引导表语从句。
1．引导表语从句的连接词主要有以下几类 (1)连接词that/whether
that和whether在表语从句中不作任何成分，that无实义，但whether仍保留“是否”的意义。
Our plan is that we'll go there once a week.