"fall ill" 是英语表达患病的常用说法。来源是古英语中的 "feallan"，意思是 "失去健康"。
例句:
"I fell ill last night and had to stay home from work." (我昨晚病倒了，不得不留在家里不上班)
"He's been ill for a week now." (他已经病了一个星期了)
另外, "sick" 也是表示患病的常用词汇。
例句:
"I feel sick, I think I should stay home" (我感觉不舒服，我想我应该呆在家里)
"He has been sick for a few days." (他已经生病几天了)