500
Is this a narrative or an expository? How do you know? What if you can't think of anything to write?
Suppose you could choose an extra activity to do at school. Think about an activity that you would like to do. Now write to explain what extra activity you would like to do and why you would like to do it.
What is an expository because it says "write to explain." If I can't think of anything to write, it is okay to make it up as long as I have details to support my writing.