Complex sentence: Filled with determination, Arlo wakes up and attacks the pterodactyls who have cornered Spot at the river and the two of them manage to throw them into the water where they ride helplessly downstream.
Split into simpler sentences: Filled with determination, Arlo wakes up and attacks the pterodactyls who have cornered Spot at the river. Arlo and Spot manage to throw the pterodactyls into the water where they ride helplessly downstream.