Explains how topic sentence is like top bun of hamburger 

The Top Bun

While many students have trouble with a topic sentence, they are pretty easy to write.

Like the top bun of a hamburger, they cannot be too thick. In the same way, the topic sentence has to be limited, and basically tell the reader what's going to be in the burger. If I write, "I love New York," it doesn't give any sense of the paragraph will include. But if I add, "for three reasons," now I know what's coming in the paragraph or essay -- the three reasons.

This works with any subject.

I like ice cream for three reasons.
Houses are better than apartments for three reasons.
My favorite book is The Cat in the Hat for three reasons.

While there are slight modifications depending on the paragraph or essay type, this basic structure works for all academic writing.

Now, let's move on to the first reason, the lettuce.