Need some writers! Write a narrative about a time when you did something when you thought you couldn't. (Doesn't need to be long.)

Briefly explain what the mistake was, but don't dwell on it.

Quickly switch over to what you learned or how you improved, after making that mistake.

You might also explain the steps you took to make sure that the mistake never happened again.

Explanation:

quite an interesting way to teach topic sentences, because the answer to this question is the best definition of a topic sentence that one can present, it is as if answering the questions taught you how to do it, this is some real teaching, it is terribly well-done.

the topic sentence in this paragraph is:

topic sentences writers stay on track and keep a paragraph from becoming an aimless collection of sentences about an idea.

which incidentally tells you what a topic sentence should be.

just say it's your friend did it and you had no idea?