What is an "extended passage of dialogue?"

I am not aware of specific rules for writing an extended
passage of dialogue, but I expect it is the same as writing dialogue, except that there
is no narration included.

For example, when reading a book,
there is often dialogue mixed in with descriptions of setting, other characters, plot
development, etc.  I would expect that with an extended passage of dialogue, you would
simply write dialogue without interrupting the flow of speaking.  Open a novel and look
for examples.

A passage indicates a
section that is extended; it cannot be a short writing.  To this
end, the content of the passage should be well-developed with a
specific purpose in mind.

If you
haven't been given a prompt, I would imagine a situation that you feel compelled to
discuss put into dialogue would come more easily, or perhaps a conversation you wish you
could have with someone, but make sure the topic has substance, meaning.  Provide both
sides of the conversation, one speaker to another.  Make sure to use quotation marks at
the beginning of the passage, and after the end punctuation.  For example, "Sally sells
seashells at the seashore."  (The period goes
inside the end quotation mark.)

Avoid
filler: like running on with words without clear intention.  Your professor will see
through it immediately.  If you talk for extended periods of time on the phone or
participate in debates with friends, etc., use one of these conversations as a model:
writing from something important to you provides credibility to your
writing.

In terms of conversational tags (he said/she said
phrases), without specific instructions, I would avoid them.  (she said, he explained,
they pondered, etc.)

Make sure the passage has substance.
 Proofread for spelling, grammar and punctuation.  Choose one tense and stick to it: all
present or all past. No explanation/introduction of your passage should be needed if
your content is purposeful.

Good
luck!