INTRODUCTORY IT

Introductory it is a word that is used in a sentence, not influence the since of a sentence, because the since has been carried by the other element's sentence.


Introductory it has function as a pronoun. "it" can be used as subject or object
Compare the two sentences below:
• “I liked the book and bought it”
- I : subject
- Liked : predicate/verb
- The book : object
- And : conjunction
- Bought : predicate/verb
- It : pronoun, replacing “the book”
It in the first sentence replace the book. 

• “ It is nice to be important but it is more important to be nice”

It in the second sentence refers to nothing or meaningless. It is used to complete the structure of a sentence which is Subject + Predicate + Object/Complement. we called “it” as introductory it or Impersonal it.
Impersonal “it” can be used to introduce time, weather, distance., condition etc.

THE PLACE FOR “IT”
1. in subject position

• IT + TO BE + ADJECTIVE ………………..
- It is not difficult to understand the lesson.
- It would be nice seeing him again

• IT + TO BE + NOUN ………………………
- It is a pity to spend the money that way
- It is a difficult thing doing everything by yourself

• IT + LINKING VERB + ADJECTIVE……..
- It became useless to go on
- It appears no good cheating on the test

• IT + VERB + THAT CLAUSE …………….
- It seems that she was sick
- It happened that I was not out of town

2. in object position
• SUBJECT + VERB + IT + ADJECTIVE
- I think it wrong to cheat in the examination
- I found it easy to get the best score for English
THE USES OF “IT”
a) The use of “it” in sentences about time and weather

It + Be + Noun Phrase
It Is Ten o’clock
It Is saturday

It + Be + Adjective
It Is Late
It Is Nice today

It + Verb 
It Rains in the rainy season
It Snows In the winter

b) The use of it in sentences about distance
Example 1

- From Madiun to Ngawi is 500 miles It is 500 miles from Madiun to Ngawi
Example 2
- From here to Matahari Plaza is 200 meters 
It is 200 meters from here to Matahari Plaza or
It is 200 meters to Matahari Plaza

c) Another uses of “it”

I. To infinitive(to + V1)
- To understand this lesson is easy This lesson is easy to understand or it is easy to understand this lesson
II. Being /Ving
- Being a good student is important it is important to be a good student
- Playing football is fun it is fun to play football
III. Should
- Parents should take care their children it is important for parents to take care their children

THERE 
SINGULAR
• A book is on the table there is a book on the table
• A book was on the table there was a book on the table
PLURAL
• Some books are on the table there are some books on the table
• Some book were on the table there were some books on the table

The expletive “there” has no meaning. It is used only to fill the subject position