The best way to get better at finding the main idea is to practise on many kinds of texts. Below are eight short passages, each followed by its main idea and a short explanation. Before reading each answer, try to find the main idea yourself: ask what the passage is about (the topic) and what the author says about it.
1. Informational passage
Bees are essential to farming. As they move from flower to flower, they carry the pollen that many plants need to produce fruit and seeds. Crops such as apples, almonds and cherries depend heavily on their work. Without bees, the harvest of many foods would shrink.
Main idea: Bees are essential to farming because they pollinate many crops.
Why: the idea is stated in the first sentence; the others explain how pollination works and give examples of crops.
2. Narrative passage
Maya had trained for weeks for the neighbourhood race. On the day, just a few metres from the finish line, she saw a small boy who had fallen and was crying. She stopped, helped him up and walked him back to his parents. She finished last, but the crowd cheered for her more than for anyone else.
Main idea: Helping others can matter more than winning.
Why: the idea is implied: no sentence states it, but it follows from what Maya does and how the crowd reacts.
3. Persuasive passage
Many schools have banned phones in the classroom, and I think it is the right decision. During lessons, a single notification is enough to make a student lose track of the explanation. Without phones, break time also becomes a chance to talk and play again. For these reasons, the ban helps both learning and friendships at school.
Main idea: Banning phones in class helps students learn and get along better.
Why: the claim is stated at the start and repeated at the end with for these reasons; the sentences in between are the arguments.
4. Science passage
When it is cold, the human body uses several mechanisms to keep warm. Blood vessels near the skin narrow, so less blood reaches the surface and less heat is lost. If the cold continues, the muscles start contracting on their own, and the shivering this causes produces heat.
Main idea: The human body has ways of keeping warm in cold conditions.
Why: the first sentence is general; the following ones describe two of those mechanisms.
5. History passage
Before the printing press, books were copied by hand, which made them slow to produce, rare and expensive. In the mid-fifteenth century, Johannes Gutenberg developed a movable-type printing system in Europe that could reproduce texts quickly. Within a few decades, print shops had opened in many cities and books were reaching far more readers.
Main idea: Gutenberg’s movable-type press made books cheaper and brought them to many more people.
Why: the passage compares life before and after the invention; the main idea combines the change with its result.
6. How-to passage
Before giving a presentation, rehearse it out loud several times. This helps you notice the parts that are hard to say and check how long it takes. Practising in front of a friend is also useful, since they can tell you if you are speaking too fast. With enough rehearsal, you will feel far less nervous on the day.
Main idea: Rehearsing a presentation out loud helps you give it better and with less anxiety.
Why: the main idea joins the opening advice with the benefit at the end; the rest explains how to rehearse.
7. Main idea at the end
A litre of water weighs about one kilogram, and an adult body holds dozens of litres. We lose water when we breathe, sweat and get rid of waste. Even at rest, this loss never stops. That is why we need to drink throughout the day, even when we do not feel very thirsty.
Main idea: We need to drink water throughout the day because the body loses it constantly.
Why: the facts come first and the main idea appears at the end, introduced by that is why.
8. Descriptive passage
In my grandparents’ village, the houses have white walls and flowerpots in every window. In the evenings, neighbours bring chairs out into the street and chat until it gets dark. Nobody is in a hurry, and anyone walking past stops to say hello.
Main idea: Life in the narrator’s grandparents’ village is calm and friendly.
Why: the idea is implied; every detail (the chairs in the street, the lack of hurry, the greetings) points to that overall impression.
What these examples show
- The main idea can come at the beginning (examples 1 and 4), at the end (example 7), in both places (example 3) or not be written at all (examples 2 and 8).
- It is always a complete sentence that covers the whole passage.
- Examples, facts and descriptions are supporting details that back it up.
To keep practising, take a passage from your textbook, write its main idea and then check your answer with the tool below. Do not use it to skip the thinking: the useful part is comparing the two answers and understanding why they match or differ.