Here’s the corrected version of your text with grammatical errors addressed:
The Ceratosaurus diet would mainly consist of large sauropods and sometimes aquatic animals like fish, turtles, and crocodiles. The Ceratosaurus had very long and slender teeth, which allowed it to kill and slash at prey it came across. The Ceratosaurus's teeth were measured to sometimes be over 9 inches long.
Changes made:
- Removed "it" from "which it allowed" for clarity.
- Changed "Ceratosaurus teeth was measured" to "Ceratosaurus's teeth were measured" for correct subject-verb agreement and possessive form.
- Changed "9 meters" to "9 inches" to ensure that the measurement aligns with the context of teeth length (common tooth lengths are usually in inches rather than meters, but feel free to change it back if 9 meters was intended).