all these cats had one experience in common

have 仅仅表示“ 有”have sth in common  指“共有。”意即有着相同的。如：We have nothing in common。我们没有相同之处。比较：All these cats had one experience in common所有这些猫都有着一个相同的经历       All these cats had a common experience        所有这些猫都有着一个平常的经历  2。a,和one 貌似一样的意思,但one 强调数词概念,侧重“量”