What is asked when told to elucidate the structure of any common phrase in English? Please explain with an example.

This question requires your understanding of the word
elucidate. Essentially, this means to make something clear, or to clarify what is said.
I would also imagine that you are being asked to pick a phrase that is not meant
literally but figuratively. Thus, you must identify the purpose of the phrase, thereby
making it clear.

For example, often English speakers will
say that "it is raining cats and dogs." When we do say this we do not literally mean
that cats and dogs are falling from the sky. We mean the rain is coming down so hard. We
exaggerate by substituting a small, sometimes easily provoked animal for the pelting
rain. Cats and dogs cannot fall from the sky in the form of rain. But we can often feel
that rain is nagging us and inconveniencing us like small animals can. This paragraph is
your elucidation. It makes clear how and why the phrase is
used.

You might consider looking up other idioms or
colloquialisms in the English language. You could uncover other phrases to use and
research.