Cause & Effect — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. Nora forgot to water the plant; therefore, it wilted.
No water is the cause, and the word therefore shows that the wilted plant is the clear effect.
2. Max did not wear his helmet; that is why his mom stopped him.
Riding without a helmet is unsafe, so the phrase that is why points to mom stopping him.
3. The hallway was wet; therefore, we had to walk slowly.
A wet floor is the cause, and the word therefore introduces walking slowly as the safe effect.
4. Ella studied her spelling every night; that is why she got a good grade.
Studying is the cause, and the phrase that is why links it to the good grade effect.
5. Ken left his lunchbox open; therefore, ants found his sandwich.
An open lunchbox is the cause, and therefore signals that ants finding the food is the effect.
6. The bell rang; therefore, the class lined up quickly.
The ringing bell is the cause, and the word therefore points to lining up as the class effect.
7. Jada finished her chores early; that is why she had extra play time.
Finishing chores early is the cause, and that is why introduces extra play time as the effect.
8. Ian did not tie his shoes; therefore, he tripped on the rug.
Untied shoes are the cause, and therefore links this to tripping, which is the unsafe effect.
9. Riya packed her backpack at night; that is why she was not late in the morning.
Packing early is the cause, and that is why points to being on time, meaning not late, as the effect.
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 sink was left on
→ therefore, water spilled on the floor
therefore, water spilled on the floor
Owen did not look both ways
→ therefore, his mom stopped him at the curb
that is why the teacher asked for quiet
The library was very noisy
→ that is why the teacher asked for quiet
therefore, his mom stopped him at the curb
Sam packed his homework at night
→ that is why he turned it in on time
that is why he turned it in on time
Signal words like therefore and that is why link a cause to its effect, so we pair them by meaning.