TASK DEFINITION: In this task you need to give reasons to justify the pronoun coreference relations. Each of the provided inputs contains a sentence with a target pronoun and a question about how to justify the coreference between a noun phrase and the target pronoun. Good practices involve the discussion about how the descriptions attached to the targeted pronoun relate to the noun phrase candidate in the question. The reasoning could come from one or multiple following knowledge types about commonsense: First: 'Property', the knowledge about property of objects (e.g., ice is cold). Second: 'Object', the knowledge about objects (e.g., cats have ears). Third: 'Eventuality', the knowledge about eventuality (e.g., 'wake up' happens before 'open eyes'). Forth: 'Spatial', the knowledge about spatial position (e.g., object at the back can be blocked). Fifth: 'Quantity', the knowledge about numbers (e.g., 2 is smaller than 10). Sixth: all other knowledge if above ones are not suitable. Write the sentence in natural language.
PROBLEM: Sentence: This morning, Joey built a sand castle on the beach, and put a toy  flag in the highest tower, but this afternoon the tide  knocked it down.
 Question: Why does the 'it' refer to the sand castle?

SOLUTION: Because the castle would be knocked down by the tide first.

PROBLEM: Sentence: Fred is the only man still alive who remembers my great-grandfather. He is a remarkable man.
 Question: Why does the 'He' refer to fred?

SOLUTION: Because "is" is present tense and indicates he is still alive.

PROBLEM: Sentence: Sam took French classes from Adam, because he was known to speak it fluently.
 Question: Why does the 'he' refer to adam?

SOLUTION:
Because Sam was taking lessons.