What is the central and most important idea of a reading passage.?

The central and most important idea of a reading passage is called the main idea. It's the overarching point the author wants to convey to the reader.

Here's how to find the main idea:

* Look for the topic: What is the passage generally about?

* Identify the author's purpose: Why did the author write this? To inform, persuade, entertain, or something else?

* Summarize the key points: What are the most important pieces of information presented?

* Find the controlling idea: This is the statement that unites all the supporting details and explains the author's main point.

Think of it this way: If you had to explain the passage in one sentence, what would it be? That sentence would express the main idea.

Examples:

* Passage: "The Great Wall of China is one of the most impressive feats of engineering in human history. It was built over centuries, stretching for thousands of miles and employing millions of workers. The wall serves as a testament to the power and resilience of the Chinese people."

* Main idea: The Great Wall of China is a significant historical and architectural achievement that showcases the strength and perseverance of the Chinese people.

* Passage: "Climate change is a serious threat to our planet. Rising temperatures, melting glaciers, and extreme weather events are all consequences of human activities that release greenhouse gases into the atmosphere. Urgent action is needed to reduce our carbon footprint and mitigate the effects of climate change."

* Main idea: Climate change is a major environmental crisis caused by human activities, and we need to take immediate steps to address it.

Remember, the main idea may not be explicitly stated, so you might need to infer it from the information presented.