Cause and Effect — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. The candle went out because a strong gust of wind blew through the window.
Wind blows out a flame by pushing the burning gases away from the wick. The word 'because' points to that gust of wind as the reason the candle went out.
2. He practiced his speech many times, so he felt confident on stage.
The word 'so' points to the result of an action. Lots of practice gave him the confidence he showed when it was time to speak.
3. Since the pool was closed for cleaning, the children went to the lake.
'Since' opens the sentence and is capitalized as the first word. The pool being closed forced the children to find a different place to swim.
4. The pipes froze overnight. Therefore, no water came out of the faucet.
'Therefore' starts a new sentence to point out the result. Frozen water inside pipes blocks the flow, which is why nothing came out of the faucet.
5. The rabbit dug a burrow because it needed a safe place for its babies.
Mother rabbits dig underground tunnels to protect their babies from predators. The word 'because' shows that this need is the cause of the digging.
6. She mixed the paint colors together, so the water turned brown.
When many paint colors mix, they turn into a muddy brown shade. The word 'so' connects the mixing action to the brown water that resulted.
7. Since the batteries died, the flashlight stopped working.
Flashlights run on power from batteries, so dead batteries mean no light. 'Since' starts the sentence to introduce that cause.
8. The farmer planted seeds in the spring. As a result, fresh vegetables grew by summer.
The phrase 'as a result' is a signal that introduces an effect. Planting seeds in spring led to vegetables ready to harvest by summer.
9. Nobody remembered to feed the fish, so it was very hungry by evening.
The word 'so' shows the natural effect of an action. A skipped meal leaves any pet hungry, which is exactly what happened to the fish.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
The boy left his bike in the driveway.
→ The car backed over the bike.
He had energy all day at school.
She studied her map before the trip.
→ She did not get lost along the way.
The car backed over the bike.
The campfire was not put out properly.
→ The dry grass caught fire.
She did not get lost along the way.
He ate a big breakfast every morning.
→ He had energy all day at school.
The dry grass caught fire.
Each cause leads logically to its effect: a bike in the way gets run over, knowing the route prevents getting lost, hot embers in dry grass spread flames, and a hearty breakfast fuels the body for hours.