Question

英语句子成分

The FBI has admitted it received a tip-off about him last year.（来源是BBC新闻的一篇报道）

我想问一下，就我看来it后面那一段是定语从句的一部分，先行词是it，那关系代词为什么被省略？
或者这不是定语从句，而是什么？
我想明白了。
过去分词短语做IT后置定语。
学语法有些懵了。

Answer 1

概念
句子是由词按照一定的语法结构组成的。组成句子的各个部分叫做句子的成分。句子的成分包括：主语、谓语、表语、宾语（直接和间接宾语）、宾语补足语、定语和状语。主语和谓语是句子的主体部分（在英语中，一般句子必须有主语和谓语），表语、宾语和宾语的补足语是谓语里的组成部分。其他成份如定语和状语是句子的次要成分。
▲句子成分分类
1．主语
主语是谓语讲述的对象，表示所说的“是什么”或“是谁”。一般由名词、代词、不定代词或相当于名词的单词或短语来充当，也有从句充当的现象。大多数主语都在句首。如： 讲述“谁” We work in a big factory.
讲述“什么” The classroom is very big.
数词作主语 Three are enough. 三个人就够了
不定式作主语 To operate on the blind is one of the ORBIS Doctor’s job.
从句作主语 What we need is food. 我们最需要的是食物.
▲ 在“There be …”句型中，主语的位置在中间。
如： There are some bottles of milk in the box.
▲ 在个别句型中，主语在整个句子后面，这时前面用it作形式主语。如：
It is very interesting to play the game called “treat or trick”.
It took two workers about three months to build the house.
2．谓语 谓语时用来说明主语“做什么”、“是什么”或“怎么样”，谓语必须是动词，谓语和主语在“人称”和“数”两方面必须一致。如：
He is very generous.
She looks very smart and cool We have finished the job.
He can speak German.
3．表语
表语说明主语“是什么”或“怎么样”，由名词、形容词、介词、副词、不定式及相当于名词的词或短语来充当，它的位置在系动词后面。
形容词作表语 You look younger than before.
名词作表语 My father is a teacher.
副词作表语 Everyone is here.
介词短语作表语 They are at the theatre.
不定式作表语 My job is to teach them English.
动名词作表语 Her job is training the nurses.
从句作表语 That is why he didn’t come to school yesterday.
4．宾语
▲宾语是动作、行为的对象，由名词、代词、不定式、或相当于名词的词或短语或从句来充当，它和谓语动词一起说明主语是什么，通常放在谓语动词后面。有时，会有双宾语。如：
名词作宾语 He never forgives others for their mistakes. 代词做宾语 He often helps me.
不定式作宾语 He likes to sleep in the open air.
动名词作宾语 The Americans enjoyed living in China.
从句做宾语 I believe that they can finish the work in time.
▲直接宾语和间接宾语
及物动词作谓语时，后面要跟宾语，宾语分直接宾语和间接宾语。直接宾语是及物动词的对象。但有些动词除了直接宾语外，还需要有一个间接宾语，间接宾语表语动作是对谁做的，所以只能用名词或代词来充当。
如： We brought them some food.
主 谓 间宾 直宾
间接宾语可以放在直接宾语后面，但必须加to 或 for。
5．宾语的补足语
在英语的句子中有些句子里只有宾语并不能表达完整的意思，还必须在宾语后面加上宾语的补足语才能表达完整的意思。我们把“宾语＋宾语补足语”合起来称为复合宾语。复合宾语所表达的意思相当于一个巨资的意思。名词、动词、形容词、副词、介词短语、不定式、现在分词、过去分词都可以作宾语补足语.如:
名词作宾补 If you let me go, I’ll make you king. 形容词作宾补 Don’t make your hands dirty.
副词作宾补 We found Li Ming out when we arrived.
介词短语作宾补 Make yourself at home.
省略to的不定式作宾补 I saw a girl go into the building.
带to的不定式作宾补 The boy ordered the dog to lie down.
现在分词作宾补 The boss kept them working all day.
过去分词作宾补 Yesterday he got his leg broken.
在英语中,常见的“宾语＋宾语补足语”的结构有：
▲“宾语+名词”。常用于改结构的动词有：call, name, make, find, choose, think, leave等。
We call him Jack.
They made Li Lei their monitor.
▲“宾语+形容词”。
常见的动词有think, believe, leave, drive, make, keep, turn, wish, want等。如：
Do you think his idea wrong?
We must keep our classroom clean.
We can’t leave him alone.
Can you get everything ready for the party before Friday?
▲“宾语+副词”。副词作宾补常表示宾语的状态，与宾语有逻辑上的主表关系。常见的副词有：down, up, here, there, home, in, out, anywhere等。
如： Let him in/ out.
Mr. Li drove us home.
When got there, we found him out.
▲“宾语+介词短语”。介词短语作宾补常表示其逻辑主语（即宾语）所处的状态，两者有主表的关系。如：
We found everything in good order.
We regard him as our good friend.
He opened the door and found some of his friends in the rain.
▲“宾语+不定式”。充当宾补的不定式有三种：
A 要求带to的不定式
The cool water of the lake invited us to swim.
B 要求不带to 的不定式 let, make, see, hear, watch等
The boss made the workers work 12 hours a day.
I often hear him read English in his room.
C 单词help 后可加 to 或不加 to
She sometimes helps her mother (to) do housework.
▲“宾语+现在分词”。
现在分词作宾补，此时在该句型中的宾语即为现在分词逻辑上的主语，有着主谓关系。
I saw them playing on the playground.
I heard Mary singing in the classroom.
▲“宾语+过去分词”。宾语和宾补之间是被动关系，过去分词表示被动和完成。
I had my bike stolen.
The teacher explained again and again to make himself understood.
▲ 形式宾语＋形容词 We found it impossible to get there before Saturday.
▲宾语+what 从句 Call me what you like.
Mr. Li has made the factory what it is today.
The mountain village is different from what it was ten years ago.
6．定语
▲ 定语用来修饰名词或代词。形容词、代词、数词、名词、介词短语、不定式或相当于形容词的词或短语等都可以充当定语。因为它是修饰名词或代词的，而名词和代词可以作主语、表语或宾语，所以定语的位置很灵活，凡是有名词、代词的地方都可以有定语。如： 形容词作定语
The black bike is mine.
代词作定语 What’s your name?
名词作定语 They made some paper flowers.
介词短语作定语 The boys in the room are in Class Three, Grade One.
不定式作短语 I have lots to eat and drink.
从句作定语 The tall boy who is standing there is Peter.
▲ 在英语中，并不是所有的定语都放在被修饰词的前面，有的是放在被修饰词的后面，故称“后置定语”。
▲ 修饰不定代词 something, anything, nothing, something, anyone, somebody, anybody, nobody 的定语必须后置。如：
We’ll go to have something English.
If you don’t know the answer, ask someone else.
Do you have anything important to tell me?
▲介词短语作定语时要后置。如：
Do you know the boy behind the tree?
The students in the room are all my friends.
I think the picture on the left is better than the one on the right.
▲动词的不定式作定语时要后置
What about something to drink?
I have no time to travel to China is in Autumn or in Spring.
注 动词不定式作主语时，to 后面的动词必须是及物动词或相当于及物动词的短语。如果时短语时，那么与动词搭配的介词或副词是不能少的。
Do you have any piece of music to listen to?
▲nearby, below, downstairs等个别方位词作定语时要后置。如：
We are at the top of the hill.
Can you see the village below?
The people downstairs are listening to a talk now?
They took the boy to the hospital nearby at once.
7．状语 状语用来修饰动词、形容词或副词。它表示行为发生的时间、地点、目的、方式、程度等，一般由副词、介词短语、不定式，从句或相当于副词的词或短语来充当。状语一般放在句末，但有时也可以放在句首、句中。如：
He did it carefully.
They missed me very much.
Without his help, we couldn’t work it out.
In order to catch up with my classmates, I must study hard.
When I was young, I could swim well.

Answer 2

学好从句之前学好句子的成分很重要。