Here is a friendly grammar check for a 7-year-old.
Original sentences:
Our heart is a strong muscle about the size of our fist. We live as long as it pumps blood through tubes called blood vessels.
Corrected sentences (two good options):
Option 1 (simple): Our heart is a strong muscle about the size of your fist. We stay alive as long as it keeps pumping blood through tubes called blood vessels.
Option 2 (one sentence): Our heart is a strong muscle about the size of your fist, and we stay alive as long as it keeps pumping blood through tubes called blood vessels.
Why these changes?
- 'Your fist' — this makes the sentence feel personal and easy to picture. 'Our fist' is not wrong, but 'your' is clearer for each reader.
- 'We stay alive' sounds clearer than just 'we live' when talking about what the heart does.
- 'Keeps pumping' shows that the heart must keep working all the time; it explains the continuous action better than just 'pumps.'
- 'Blood vessels' is correct and a good way to name the tubes that carry blood.
The original was understandable and mostly correct. These small changes make it clearer and more natural for a child to read.
Would you like an even shorter version for a younger child?