My e-primbon Part 2

A. To understand this lesson is easy.

B. It is easy to understand this lesson.

In this pattern, it has no meaning. It is used only to fill the subject position in the sentence. Thus, it is called introductory “it”.

A and B mean the same thing, but sentence B is more common and useful than A. A was introduce mainly to make the meaning of C easier to understand.

Introductory “it” can fill the position both of the subject and object.

Introductory “it” as a subject:

To watch musical programs is pleasant.

It is pleasant to watch musical program.

To play football must be fun.