造句:一句人作主语的，一句物作主语，一句it做形式主语，两句事做主语的句子（句式要难，比如定语从句之类的....)

造句:一句人作主语的，一句物作主语，一句it做形式主语，两句事做主语的句子（句式要难，比如定语从句之类的....)
希望是中考级别的，加一些难句式

解题思路： 此题涉及英语中的多个语法知识点，也是英语学习中的难点，注意积累与练习
解题过程：
一、人做主语：Tom told a joke but it fell flat.汤姆说了个笑话，但没有引人发笑。
You're not far wrong.你差不多对了。
二、物作主语：A tree has fallen across the road.一棵树倒下横在路上。
Little streams feed big rivers. 小河流入大江。
三、it作形式主语:
动词不定式，动名词或主语从句作主语时，通常把它们放在谓语动词前，而用it作形式主语，放到句首，常见句型有：
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 remains a question whether he will come or not.
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 not decided who will give the operation to the patient.
4. It + 不及物动词(seem, appear, happen等) + 主语从句, 这类不及物动词有：appear, happen, seem等，如：
It seemed that he didn’t tell the truth.
5. It + be + 形容词+ for sb.）+ 动词不定式 这类句型常用形容词easy, difficult, hard, important, possible，wise等作表语，有时候为了强调不定式动作的执行者，常在不定式前加for sb，如：
It is unwise to give the children whatever they want.
这类形容词有：easy, difficult, hard, important, possible，wise
6. It + be + 形容词 + of sb. + 动词不定式，这类形容词常是表示心理品质,性格特征的形容词，如：kind, nice stupid, clever, foolish, polite, impolite, silly, selfish, considerate等。
某人和这些形容词可以构成主系表结构。如：
It’s very kind of you to help me with the work. =You are kind to help me.
7. It + be +名词词组 + 动词不定式，如：
It is not a good habit to stay up too late.
8. It + be + 名词或形容词+ 动名词，这类名词和形容词常常是：good, no good, no use, a waste of, useless, senseless等，如：
It is no use arguing about the matter with him.
9. It + take ( sb. )+ 时间（金钱）+ 动词不定式，如：
It will take a whole day to get to the top of the mountain on foot.
四、从句用作主语，如：
Whenever you are ready will be fine. 你无论什么时候准备好都行。
When we are going to have an English test has not been decided.什么时候我们会有一个英语测验还没有决定。
主语从句作主语其谓语形式较难把握，讲解如下：
主语从句做主语，主句谓语动词的单复数需根据从句表示的单复数意义决定。
1．what引导的主语从句做主语
（1）通常情况下，由what引导的主语从句放在句首时，其后的谓语动词，按语法一致的原则用单数。eg:
What she said is correct.
What caused the accident is not clear.
（2）当主句中的表语是复数形式，或what从句的谓语动词及其补足语均为复数形式时，主句的谓语动词应用复数。eg:
What he gave me are five English books.
What are used as chief building materials today are steel and concrete.
（3）当what引导的主语从句是一个由and连接的并列结构时，应根据句意确定其表达的单复数意义，然后决定主句谓语动词的单复数形式。 eg:
What he says and acts does not concern me.
What he says and acts do not agree.
What I say and what I think are no business of yours.
2．由其它词引导的从句做主语时，谓语动词用单数形式。
Whether they will hold a party or not has not been decided.
Who is responsible for the accidents is not clear.
3．当同一个主语从句是由两个不同的引导词引导时，因为它表达的还是同一件事，因此，谓语动词一般用单数。 eg:
When and where we should hold the meeting has not been decided yet.
4．当主语是由两个由and连接的主语从句组成，通常表示的是两件不同的事情，主句谓语动词需用复数形式。
What you eat and how much you exercise are important factors in a weight loss program.
What caused the accident and who was responsible for it remain a mystery to us.