I know what you mean, but I needed help to have a go.
Before I post the question, I made sure the meaning of every word in the part of the elegy, but I couldn't build a sentence from them, so I asked.
I hope you understand that poems are often truly unintelligible when written in a foreign language which is so different from your own language.
Also, it's not homework from school or anything.
Thank you Anglika. Purr?
What I wanted to know is what it would be like when it is written in a sentence with the proper subject and proper order of words without inversion or ommision.
So it will be like
The cat warmly expressed his gratitude when caressed by his master and never failed his thanks to purr whennever he stroked his sable fur.
if we use all the words in the elegy and add the subject "the cat".
It makes sense.
But there is "who" in the beginning, so
The cat who warmly expressed his gratitude when caressed by his master and never failed his thanks to purr whennever he stroked his sable fur.
Then there will be no predicate. This is the consusing part.
Is is OK to use omit the the subject and predicate because it is a poem?
Poetry does not need to follow grammar rules - it is governed by metre and rhyme, and if that means omitting the subject and / or predicate [or rather, allowing the reader to infer the subject], then it is acceptable to do so.
Of course, in this case the lines you have quoted are only a part of longer poem, and the cat is referred to in the previous lines. Here is the full text: The Southern Johnsonian March 2000