I can say it’s a metaphor because here the sorrow becomes linked with the sea and basically these things have no common connections.
To get more details about what the metaphor is follow this link http://learn.lexiconic.net/metaphor.htm
Hope this help, enjoy!

In fact, dancing styles have undergone significant changes since the 1950s. In those years, the distinguishing feature of dances was that there were couples dancing. People touched each other, held their hands and performed various movements together. After the 1950s, dancing styles became absolutely different. Now, people were dancing on their own and just looked at their partners if they wanted.
Also, the dance itself became more free. There was no need to learn particular movements, everything needed was to move the body the way one felt it was right. You can observe this in modern schools as well. Girls and boys dance in separate circles. It is good to some extent because nobody should wait to be asked to join the dance.

Self-iterested, maybe. Or self-oriented.
If you want a stronger expression, check the Urban dictionary, lol

First and foremost, you are to decide which aspect you know really well. What I mean, is that you won’t be able to find persuasive arguments unless you are good at the subject. For example, I know psychology so I would take some syndrome, describe its specificity, employ some research in my paper and so on.
Don’t take the topic that just seems to be the simplest. Such questions as drugs legalization are too obvious; teachers are tired of reading the same statements over and over again. Work out a logic structure.
Why is the problem important? What has already been done about it? What needs to be done?
What’s your attitude towards the issue? Be concise, yet convincing!

One of the most important aspects that should not be disregarded is that inventions should have some utility most of the time.
An invention that has no benefits may be regarded as useless most of the time.

Such paragraphs may be hard to write for some because it is necessary to understand how to summarize your ideas. It is important to ensure that transitions are smooth because it may affect the level of readability.
It would be great if you have provided a topic for this paper because we do not know what kind of an essay you have to write, and this information could be incredibly valuable.