Determine the main idea of a passage
Definition of the Main Idea:
The main idea is the central point or the most important concept that the author wants to communicate to the reader.
Importance of the Main Idea:
- Helps understand the overall message of the passage.
- Serves as a foundation for identifying supporting details.
Steps to Identify the Main Idea:
- Read the Passage Carefully: Focus on the title, first, and last sentences.
- Look for Repeated Ideas: Identify themes or concepts that are mentioned multiple times.
- Summarize the Passage: Try to express the passage in one sentence.
- Eliminate Irrelevant Details: Distinguish between supporting details and the overarching idea.
Clues to Find the Main Idea:
- Topic Sentences: Often located in the first or last sentences of paragraphs.
- Key Words: Words that are emphasized or repeated.
- Context of Supporting Details: How examples and facts relate to the overall message.
Types of Main Ideas:
- Explicit Main Idea: Clearly stated within the text.
- Implicit Main Idea: Requires inference based on the details provided.
Common Mistakes to Avoid:
- Confusing supporting details with the main idea.
- Overgeneralizing or underestimating the passage’s message.
- Focusing on minor details instead of the big picture.
Let’s practice!
Read the passage.
AC vs DC
In the 1880s, the War of the Currents began. Thomas Edison developed direct current, or DC, a type of electricity that flows in one direction. By 1887, DC was in use around the United States. It had some drawbacks, though. Converting it to lower or higher voltages was difficult; that is, the current’s force couldn’t be changed easily. Transmitted at the low voltage needed for use in homes and businesses, it lost power after travelling only one and a half kilometres. Meanwhile, Nikola Tesla was working with alternating current, or AC. AC reverses direction many times per second and can be changed to different voltages. At high voltage, it can be transmitted efficiently, travelling hundreds of kilometres with little energy loss. Because of its advantages, AC triumphed by the end of the nineteenth century.