This is very. Interesting-
Clauses highly improve sentence structures. They can make the sentence sound a lot better to the tongue, and it even make the sentence easier to understand. I hope this helps! :)
The diction of the story depend on the plot anh the theme of the story so you need to make the question more specific to answer.
This passage uses repetition to create a haunting effect in two different ways. The first way repetition is used is through literal repetition, repeating the phrase "my darling" and ending both of the final lines with the word "sea". The second form of repetition that creates this effect is the repetition of an idea. A sepulchre is an area where a person is buried, and so is a tomb, so the final two lines have the same meaning.
The change in end rhyme in from the first two lines to the last two lines is also significant, because it changes the focus of the poem from mourning the person who has been laid to rest, to the place in which she has been laid to rest.