Usage of be verb

[kahhong]

Be verb has 4 usage.


1.Exist: Occupy a position
eg: The shop is on the corner.

2.Happen; take place
eg: The wedding is tomorrow.

3.to join subject and complement
eg:He is my teacher.

4. to form part of other verbs
eg: it is raining.


I dont understand the 3rd one, could someone explains to me, thanks?
which 1 is subject and complement for "he is my teacher"

[rewboss]

"He" is the subject, and "my teacher" is the complement.

In this usage, you can think of the verb as an equals sign:

He = my teacher.

That is,

subject = complement