In this task, You are given an open-domain question that can be answered based on factual information. Your task is to provide \*short\* answer (in a few words only) for the given question. The short answer can be one or more entities or it can also be boolean \*yes\* or \*no\*.

Q: when does project blue book come out on history channel

A: January 8, 2019
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Q: what were the cause of the american civil war

A: conflicts over slavery
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Q: who was ancient china's main enemy that lived to the north

A:
Sui Dynasty
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