Your topic sentence or thesis statement should focus on only one main point. Two main points can split and weaken the focus of the writing.

MAIN IDEA WITH TWO MAIN POINTS

High schools should sell healthy food instead of junk food, OR they should start later in the morning.

The two main points are underlined. Although both are good main points, together they split both the writer’s and the readers’ focus. The writer would need to give reasons to support each point, and the ideas are completely different.

MAIN IDEA WITH A SINGLE MAIN POINT

High schools should sell healthy food instead of junk food.

OR

High schools should start later in the morning.