come down 下来，降落；流传下来；倒塌；落魄，失势
eg.
下降，落下：
Her temperature came down in the evening.
到了晚上她的体温就降下来了。
(物价等)跌落：
The price of coal has come down this week.
本周煤价跌落下来。
下(雨、雪等)：
The rain came down in bucketfuls.
大雨倾盆而下。
崩溃；掉下；垮：
The roof came down on our heads.
屋顶掉下来砸在我们头上。
由城市等大地方到乡下等小地方：
He came down from Shanghai last year and settled in the village.
他去年从上海来到农村定居。