Main Idea & Supporting Details — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. Apples can be red, green, or yellow. They grow on trees. They taste sweet or sour. This passage is mainly about apples.
Every sentence in the passage tells something about apples, so the main topic is apples.
2. Dogs wag their tails when happy. They bark to warn you. Dogs like to play fetch. The main idea is that dogs communicate in many ways.
The details show different ways dogs communicate: wagging, barking, and playing.
3. Rain fills rivers and lakes. Plants need rain to grow. Rain helps keep the earth green. The main idea is that rain is helpful.
All the details show ways that rain helps, so the main idea is that rain is helpful.
4. The moon shines at night. It changes shape each week. Sometimes we see a full moon. This passage is mostly about the moon.
Every sentence gives information about the moon, so the passage is mostly about the moon.
5. Bees make honey. They visit flowers to get nectar. Bees live in hives together. The topic of this passage is bees.
All the details are about bees, so the topic of the passage is bees.
6. A sentence that gives extra facts about the main idea is called a supporting detail.
A supporting detail is a sentence that gives extra facts or information about the main idea.
7. The main idea answers the question: What is this passage mostly about?
The main idea tells what the passage is mostly about.
8. When you retell a story, you share the main idea and the key details.
A good retelling includes the main idea and the most important details.
9. A good title for a passage usually hints at the main idea.
A good title gives the reader a hint about the main idea of the passage.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Cats sleep up to 16 hours a day. They groom themselves. Cats purr when happy.
→ Cats spend their day resting and caring for themselves.
The sun is important to life on Earth.
The sun gives us light. It keeps us warm. Plants need the sun to grow.
→ The sun is important to life on Earth.
Frogs are interesting animals.
Frogs live near water. They jump very far. Baby frogs are called tadpoles.
→ Frogs are interesting animals.
Riding a bike is fun and safe.
Bikes have two wheels. You pedal to move. Helmets keep riders safe.
→ Riding a bike is fun and safe.
Cats spend their day resting and caring for themselves.
Each set of details supports one main idea that tells the big message of the passage.