A phrase is a combination of poetry and what grammar?

A phrase is strictly a sentence pattern.

It's just that this sentence has a special rhythm of poetry.

The only difference between sentence patterns and sentence patterns is that there may not be rich sentence elements.

take for example

I love you, both subject and object.

But loving you is a word. It has no subject. This is a verb-object phrase.

It is this simplicity that creates its rhythm.

Things are different, this is an idiom and a phrase. This description without branches and leaves highlights the grandeur of this word.

I wish you progress in your study, hehe