It seems that you are looking to fill in some blanks related to the general subject of a text and the most important idea in a text. Based on the context provided, here are the likely responses:
General Subject: topic
Most Important Idea: main idea
Authors Use ... to Support: details/examples/evidence
So a filled-out response might look like this:
The topic is the general subject of a text, and the main idea is the most important idea in a text. Authors use details/examples/evidence to support the main idea.
If you need to clarify or adjust any specific terms, please let me know!