Come down with something：
To start to suffer from an illness, especially one that is not serious.
意思是“身体不舒服，生病”，它尤其用来指“某人感到不适、有要生病的迹象”。在使用中，人们通常用现在进行时态 “I am coming down with something.” 来表示“自己要生病了”。
例句
I think I’m coming down with something. I’ve got a bad headache.
我觉得我要生病了。我头疼得厉害。
You look red in the face and you’re coughing a little bit. Are you coming down with something?
你满脸通红，还有点咳嗽。你是不是要病了？
I’m sorry but Sandra won’t be joining us as she’s come down with the flu.
非常抱歉，桑德拉得了流感，所以不能来参加我们的活动了。
