Infinitive Clauses With Impersonal It

INFINITIVE  CLAUSESE WITH IMPERSONAL IT

“IT” is used to replace a clause or phrase at the the beginning of a sentences :

When an INFINITIVE is a subject of a sentence, we
usually begin the sentence with “it” and put infinitive
later.

For examples:
It is easy to criticize.  =  To criticize is easy.

It is better to be early. = To be early is better.

When a GERUND as a subject of a sentence, we usually begin
the sentence with “it” and put gerund later.

For examples:
It is easy talking. = Talking is easy.
It is difficult answering your questions. = Answering your questions is difficult.

It´s ( not)	Adjective	Infinitive clauses
It´s	Essential	Not to strain the muscle
It is	Important	To keep the shoulder relaxed
It is not	Necessary	To see a doctor
It is	Better	To speak to a prodessional

Funtion:

Use the adjective to describe an action

Use the adjective to describe a situation

"IT" IS + ADJ	"FOR" PRN	INFINITIVE CLS
It's difficult	for me	to guess what will happen.
It's hard		to know when a rat will get loose.
It's impossible	for us	to do  this project in 24 hours
It's important		to take a break twice a day.
It's possible	for you	to work on your own project.
It's exciting	for us	to be  here.
It's likely	for it	to get cold in the laboratory.