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: I doubt you can help me in understanding this.

SOLUTION: acceptable

PROBLEM: Mary reported John to have loved her.

SOLUTION: acceptable

PROBLEM: Any woman standing under that tree is Mary's friend.

SOLUTION:
unacceptable