When a paragraph lacks a clear sentence that states the main idea, you can infer the main idea by analyzing the supporting details and overall theme presented in the paragraph. Look for recurring concepts or topics that are emphasized, as they often point to the central idea. Additionally, consider how the details relate to one another to construct an understanding of the paragraph's focus. Ultimately, the main idea is the overarching concept that ties all the details together.
a topic sentence
The topic sentence summarizes the main idea of a paragraph and supports the thesis.
If you mean what sentence in the paragraph contains the main idea then it would be the topic sentence and the rephrased version of the conclusion.
if a paragraph does not have a topic sentence then
simple sentence with the main idea.
Topic sentence
The topic of the paragraph.
Implied Main Ideas sometimes,there is no topic sentence in a paragraph. this does not mean,that there is no main idea. (implied) (:-)
The sentence that introduces the paragraph's main ideaa sentence that introduces the subject of the paragraph.
Topic Sentence
Topic sentence
It restates the main idea of the paragraph using different words.