问题描述：
It is possible that tubes made from animal bones were used for..(were used for的主语是tubes吗>)
It is possible that tubes made from animal bones were used for spraying because hollow bones.不用翻译.另外made form animal bones 是不是插入语?were used for的主语是tubes吗
It is possible that tubes made from animal bones were used for spraying because hollow bones.不用翻译.另外made form animal bones 是不是插入语?were used for的主语是tubes吗
问题解答：
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