Well where's the paragraph ?
Answer:
Topic sentences help the reader not to miss the connection between the main idea and details. A paragraph's structure determines its purpose. A single paragraph can use elements of exposition, description, and narration. ... The concluding sentence should restate or summarize the content of the topic sentence.
The preposition is 'I' I think. I could be wrong.
Since you're going into instrument like problems the simple letter would be J
