TASK DEFINITION: You're given a sentence and your task is to classify whether the sentence is acceptable or not. Any sentence which is grammatically correct, has a naturalistic text, is written by a native speaker and which minimizes superfluous content is acceptable, otherwise unacceptable. If the sentence is acceptable then write "acceptable", otherwise "unacceptable".
PROBLEM: He's the happiest that I've ever seen him.

SOLUTION: acceptable

PROBLEM: I know a boy mad at John.

SOLUTION: acceptable

PROBLEM: They believe Charles Darwin's theory of evolution is just a scientific theory.

SOLUTION:
acceptable