____some mammals came to live in the sea is not known.能用which吗
问题描述：
____some mammals came to live in the sea is not known.能用which吗
答
不能,因为which 一般在句中会做某一个成分,即没有Which 句子不完整,而本句不看空白处,some mammals came to live in the sea is not known是一个相当完整的句子,主语是some mammals came to live in the sea .is not...