4 sentences for below freshman in high school and from freshman to senior closer to 6. The first sentence should always describe what you will cover in that particular paragraph, and you should have around 3-4 body sentences going into specific detail about the section of material in that paragraph.Then the final conclusion sentence should wrap up the paragraph.f you're in high school, a paragraph should be at least 5 sentences. If you're in middle school, four sentences might be sufficient.