Present Continuous Sentence

by Abdou
(Algeria)

Hi Diana,
I would like to know if this sentence is grammaticly correct or not. The postman knocking at the door. I saw this sentence written like this, no verb ''to be''. By the way, I wish you good marriage.

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Hi Abdou,

In a certain context it could be used.

For example, if there are two postmen that you are thinking about and someone asks you, which postman do you think is nicer? You could respond, "The postman knocking at the door".

That is to say, that you are identifying which postman you are speaking about.

You could also use it, if the sentence continued to say something else.

The postman knocking at the door is my cousin.