cat是猫，dog是狗，fight like cat and dog“激烈地争吵，吵吵闹闹，激烈地争执”。

【例句】
They always fight like cat and dog though they still love each other very much.
尽管他们彼此深爱着对方，但经常激烈地争吵。

My older brother and I used to fight like cat and dog when we were younger. We argued all the time.
我和我哥哥小的时候吵得很厉害，一天到晚吵个不停。