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.

Sentence: I was trying to open the lock with the key, but someone had filled the  keyhole with chewing gum, and I couldn't get it in.
 Question: Why does the 'it' refer to the key?
Because The keyhole hole already had chewing gum in it. They tried to put the key in, but couldn't.

Sentence: Fred is the only man still alive who remembers my great-grandfather. He was a remarkable man.
 Question: Why does the 'He' refer to my great-grandfather?
Because was is past tense and suggests it is talking about the great-grandfather who is no longer alive.

Sentence: In July, Kamtchatka declared war on Yakutsk. Since Yakutsk's army was much  better equipped and ten times larger, they were defeated within weeks.
 Question: Why does the 'they' refer to kamtchatka?

Because Yakusk had a bigger and better army. Kamtchatka didn't. So Kamtchatka lost.