Linking verbs show existence, not action. A linking verb connects a subject to a noun at the end of the sentence. Here are the present tense linking verbs: am, is, are.
I am a writer.
She is my teacher.
We are students.
Notice that with these verbs – am, is, are – there is no action. These verbs show that someone exists. This existence takes place in the present tense. The existence is happening right now.
Right now, My mom is a librarian.
Right now, My brothers are builders.
Right now, I am a student.
Remember, present progressive tense also uses the verbs am, is, are, but with an –ing active verb.
My mom is reading a story.
My brothers are building a house.
Present tense linking verbs am, is, are show existence. These linking verbs connect the subject to a noun that comes after the verb.